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START-INFO-DIR-ENTRY
* As: (as).                     The GNU assembler.
* Gas: (as).                    The GNU assembler.
END-INFO-DIR-ENTRY

   This file documents the GNU Assembler "as".

   Copyright (C) 1991, 92, 93, 94, 95, 96, 97, 98, 99, 2000, 2001, 2002
Free Software Foundation, Inc.

   Permission is granted to copy, distribute and/or modify this document
under the terms of the GNU Free Documentation License, Version 1.1 or
any later version published by the Free Software Foundation; with no
Invariant Sections, with no Front-Cover Texts, and with no Back-Cover
Texts.  A copy of the license is included in the section entitled "GNU
Free Documentation License".


File: as.info,  Node: Top,  Next: Overview,  Up: (dir)

Using as
********

This file is a user guide to the GNU assembler `as' version 2.17.

   This document is distributed under the terms of the GNU Free
Documentation License.  A copy of the license is included in the
section entitled "GNU Free Documentation License".

* Menu:

* Overview::                    Overview
* Invoking::                    Command-Line Options
* Syntax::                      Syntax
* Sections::                    Sections and Relocation
* Symbols::                     Symbols
* Expressions::                 Expressions
* Pseudo Ops::                  Assembler Directives
* Machine Dependencies::        Machine Dependent Features
* Reporting Bugs::              Reporting Bugs
* Acknowledgements::            Who Did What
* GNU Free Documentation License::  GNU Free Documentation License
* Index::                       Index


File: as.info,  Node: Overview,  Next: Invoking,  Prev: Top,  Up: Top

1 Overview
**********

Here is a brief summary of how to invoke `as'.  For details, *note
Command-Line Options: Invoking.

     as [-a[cdhlns][=FILE]] [-alternate] [-D]
      [-defsym SYM=VAL] [-f] [-g] [-gstabs]
      [-gstabs+] [-gdwarf-2] [-help] [-I DIR] [-J]
      [-K] [-L] [-listing-lhs-width=NUM]
      [-listing-lhs-width2=NUM] [-listing-rhs-width=NUM]
      [-listing-cont-lines=NUM] [-keep-locals] [-o
      OBJFILE] [-R] [-reduce-memory-overheads] [-statistics]
      [-v] [-version] [-version] [-W] [-warn]
      [-fatal-warnings] [-w] [-x] [-Z] [@FILE]
      [-target-help] [TARGET-OPTIONS]
      [-|FILES ...]

     _Target Alpha options:_
        [-mCPU]
        [-mdebug | -no-mdebug]
        [-relax] [-g] [-GSIZE]
        [-F] [-32addr]

     _Target ARC options:_
        [-marc[5|6|7|8]]
        [-EB|-EL]

     _Target ARM options:_
        [-mcpu=PROCESSOR[+EXTENSION...]]
        [-march=ARCHITECTURE[+EXTENSION...]]
        [-mfpu=FLOATING-POINT-FORMAT]
        [-mfloat-abi=ABI]
        [-meabi=VER]
        [-mthumb]
        [-EB|-EL]
        [-mapcs-32|-mapcs-26|-mapcs-float|
         -mapcs-reentrant]
        [-mthumb-interwork] [-k]

     _Target CRIS options:_
        [-underscore | -no-underscore]
        [-pic] [-N]
        [-emulation=criself | -emulation=crisaout]
        [-march=v0_v10 | -march=v10 | -march=v32 | -march=common_v10_v32]

     _Target D10V options:_
        [-O]

     _Target D30V options:_
        [-O|-n|-N]

     _Target i386 options:_
        [-32|-64] [-n]

     _Target i960 options:_
        [-ACA|-ACA_A|-ACB|-ACC|-AKA|-AKB|
         -AKC|-AMC]
        [-b] [-no-relax]

     _Target IA-64 options:_
        [-mconstant-gp|-mauto-pic]
        [-milp32|-milp64|-mlp64|-mp64]
        [-mle|mbe]
        [-mtune=itanium1|-mtune=itanium2]
        [-munwind-check=warning|-munwind-check=error]
        [-mhint.b=ok|-mhint.b=warning|-mhint.b=error]
        [-x|-xexplicit] [-xauto] [-xdebug]

     _Target IP2K options:_
        [-mip2022|-mip2022ext]

     _Target M32C options:_
        [-m32c|-m16c]

     _Target M32R options:_
        [-m32rx|-[no-]warn-explicit-parallel-conflicts|
        -W[n]p]

     _Target M680X0 options:_
        [-l] [-m68000|-m68010|-m68020|...]

     _Target M68HC11 options:_
        [-m68hc11|-m68hc12|-m68hcs12]
        [-mshort|-mlong]
        [-mshort-double|-mlong-double]
        [-force-long-branchs] [-short-branchs]
        [-strict-direct-mode] [-print-insn-syntax]
        [-print-opcodes] [-generate-example]

     _Target MCORE options:_
        [-jsri2bsr] [-sifilter] [-relax]
        [-mcpu=[210|340]]

     _Target MIPS options:_
        [-nocpp] [-EL] [-EB] [-O[OPTIMIZATION LEVEL]]
        [-g[DEBUG LEVEL]] [-G NUM] [-KPIC] [-call_shared]
        [-non_shared] [-xgot]
        [-mabi=ABI] [-32] [-n32] [-64] [-mfp32] [-mgp32]
        [-march=CPU] [-mtune=CPU] [-mips1] [-mips2]
        [-mips3] [-mips4] [-mips5] [-mips32] [-mips32r2]
        [-mips64] [-mips64r2]
        [-construct-floats] [-no-construct-floats]
        [-trap] [-no-break] [-break] [-no-trap]
        [-mfix7000] [-mno-fix7000]
        [-mips16] [-no-mips16]
        [-mips3d] [-no-mips3d]
        [-mdmx] [-no-mdmx]
        [-mdsp] [-mno-dsp]
        [-mmt] [-mno-mt]
        [-mdebug] [-no-mdebug]
        [-mpdr] [-mno-pdr]

     _Target MMIX options:_
        [-fixed-special-register-names] [-globalize-symbols]
        [-gnu-syntax] [-relax] [-no-predefined-symbols]
        [-no-expand] [-no-merge-gregs] [-x]
        [-linker-allocated-gregs]

     _Target PDP11 options:_
        [-mpic|-mno-pic] [-mall] [-mno-extensions]
        [-mEXTENSION|-mno-EXTENSION]
        [-mCPU] [-mMACHINE]

     _Target picoJava options:_
        [-mb|-me]

     _Target PowerPC options:_
        [-mpwrx|-mpwr2|-mpwr|-m601|-mppc|-mppc32|-m603|-m604|
         -m403|-m405|-mppc64|-m620|-mppc64bridge|-mbooke|
         -mbooke32|-mbooke64]
        [-mcom|-many|-maltivec] [-memb]
        [-mregnames|-mno-regnames]
        [-mrelocatable|-mrelocatable-lib]
        [-mlittle|-mlittle-endian|-mbig|-mbig-endian]
        [-msolaris|-mno-solaris]

     _Target SPARC options:_
        [-Av6|-Av7|-Av8|-Asparclet|-Asparclite
         -Av8plus|-Av8plusa|-Av9|-Av9a]
        [-xarch=v8plus|-xarch=v8plusa] [-bump]
        [-32|-64]

     _Target TIC54X options:_
      [-mcpu=54[123589]|-mcpu=54[56]lp] [-mfar-mode|-mf]
      [-merrors-to-file <FILENAME>|-me <FILENAME>]


     _Target Z80 options:_
       [-z80] [-r800]
       [ -ignore-undocumented-instructions] [-Wnud]
       [ -ignore-unportable-instructions] [-Wnup]
       [ -warn-undocumented-instructions] [-Wud]
       [ -warn-unportable-instructions] [-Wup]
       [ -forbid-undocumented-instructions] [-Fud]
       [ -forbid-unportable-instructions] [-Fup]


     _Target Xtensa options:_
      [-[no-]text-section-literals] [-[no-]absolute-literals]
      [-[no-]target-align] [-[no-]longcalls]
      [-[no-]transform]
      [-rename-section OLDNAME=NEWNAME]

`@FILE'
     Read command-line options from FILE.  The options read are
     inserted in place of the original @FILE option.  If FILE does not
     exist, or cannot be read, then the option will be treated
     literally, and not removed.

     Options in FILE are separated by whitespace.  A whitespace
     character may be included in an option by surrounding the entire
     option in either single or double quotes.  Any character
     (including a backslash) may be included by prefixing the character
     to be included with a backslash.  The FILE may itself contain
     additional @FILE options; any such options will be processed
     recursively.

`-a[cdhlmns]'
     Turn on listings, in any of a variety of ways:

    `-ac'
          omit false conditionals

    `-ad'
          omit debugging directives

    `-ah'
          include high-level source

    `-al'
          include assembly

    `-am'
          include macro expansions

    `-an'
          omit forms processing

    `-as'
          include symbols

    `=file'
          set the name of the listing file

     You may combine these options; for example, use `-aln' for assembly
     listing without forms processing.  The `=file' option, if used,
     must be the last one.  By itself, `-a' defaults to `-ahls'.

`--alternate'
     Begin in alternate macro mode, see *Note `.altmacro': Altmacro.

`-D'
     Ignored.  This option is accepted for script compatibility with
     calls to other assemblers.

`--defsym SYM=VALUE'
     Define the symbol SYM to be VALUE before assembling the input file.
     VALUE must be an integer constant.  As in C, a leading `0x'
     indicates a hexadecimal value, and a leading `0' indicates an
     octal value.

`-f'
     "fast"--skip whitespace and comment preprocessing (assume source is
     compiler output).

`-g'
`--gen-debug'
     Generate debugging information for each assembler source line
     using whichever debug format is preferred by the target.  This
     currently means either STABS, ECOFF or DWARF2.

`--gstabs'
     Generate stabs debugging information for each assembler line.  This
     may help debugging assembler code, if the debugger can handle it.

`--gstabs+'
     Generate stabs debugging information for each assembler line, with
     GNU extensions that probably only gdb can handle, and that could
     make other debuggers crash or refuse to read your program.  This
     may help debugging assembler code.  Currently the only GNU
     extension is the location of the current working directory at
     assembling time.

`--gdwarf-2'
     Generate DWARF2 debugging information for each assembler line.
     This may help debugging assembler code, if the debugger can handle
     it.  Note--this option is only supported by some targets, not all
     of them.

`--help'
     Print a summary of the command line options and exit.

`--target-help'
     Print a summary of all target specific options and exit.

`-I DIR'
     Add directory DIR to the search list for `.include' directives.

`-J'
     Don't warn about signed overflow.

`-K'
     Issue warnings when difference tables altered for long
     displacements.

`-L'
`--keep-locals'
     Keep (in the symbol table) local symbols.  On traditional a.out
     systems these start with `L', but different systems have different
     local label prefixes.

`--listing-lhs-width=NUMBER'
     Set the maximum width, in words, of the output data column for an
     assembler listing to NUMBER.

`--listing-lhs-width2=NUMBER'
     Set the maximum width, in words, of the output data column for
     continuation lines in an assembler listing to NUMBER.

`--listing-rhs-width=NUMBER'
     Set the maximum width of an input source line, as displayed in a
     listing, to NUMBER bytes.

`--listing-cont-lines=NUMBER'
     Set the maximum number of lines printed in a listing for a single
     line of input to NUMBER + 1.

`-o OBJFILE'
     Name the object-file output from `as' OBJFILE.

`-R'
     Fold the data section into the text section.

     Set the default size of GAS's hash tables to a prime number close
     to NUMBER.  Increasing this value can reduce the length of time it
     takes the assembler to perform its tasks, at the expense of
     increasing the assembler's memory requirements.  Similarly
     reducing this value can reduce the memory requirements at the
     expense of speed.

`--reduce-memory-overheads'
     This option reduces GAS's memory requirements, at the expense of
     making the assembly processes slower.  Currently this switch is a
     synonym for `--hash-size=4051', but in the future it may have
     other effects as well.

`--statistics'
     Print the maximum space (in bytes) and total time (in seconds)
     used by assembly.

`--strip-local-absolute'
     Remove local absolute symbols from the outgoing symbol table.

`-v'
`-version'
     Print the `as' version.

`--version'
     Print the `as' version and exit.

`-W'
`--no-warn'
     Suppress warning messages.

`--fatal-warnings'
     Treat warnings as errors.

`--warn'
     Don't suppress warning messages or treat them as errors.

`-w'
     Ignored.

`-x'
     Ignored.

`-Z'
     Generate an object file even after errors.

`-- | FILES ...'
     Standard input, or source files to assemble.


   The following options are available when as is configured for an ARC
processor.

`-marc[5|6|7|8]'
     This option selects the core processor variant.

`-EB | -EL'
     Select either big-endian (-EB) or little-endian (-EL) output.

   The following options are available when as is configured for the ARM
processor family.

`-mcpu=PROCESSOR[+EXTENSION...]'
     Specify which ARM processor variant is the target.

`-march=ARCHITECTURE[+EXTENSION...]'
     Specify which ARM architecture variant is used by the target.

`-mfpu=FLOATING-POINT-FORMAT'
     Select which Floating Point architecture is the target.

`-mfloat-abi=ABI'
     Select which floating point ABI is in use.

`-mthumb'
     Enable Thumb only instruction decoding.

`-mapcs-32 | -mapcs-26 | -mapcs-float | -mapcs-reentrant'
     Select which procedure calling convention is in use.

`-EB | -EL'
     Select either big-endian (-EB) or little-endian (-EL) output.

`-mthumb-interwork'
     Specify that the code has been generated with interworking between
     Thumb and ARM code in mind.

`-k'
     Specify that PIC code has been generated.

   See the info pages for documentation of the CRIS-specific options.

   The following options are available when as is configured for a D10V
processor.
`-O'
     Optimize output by parallelizing instructions.

   The following options are available when as is configured for a D30V
processor.
`-O'
     Optimize output by parallelizing instructions.

`-n'
     Warn when nops are generated.

`-N'
     Warn when a nop after a 32-bit multiply instruction is generated.

   The following options are available when as is configured for the
Intel 80960 processor.

`-ACA | -ACA_A | -ACB | -ACC | -AKA | -AKB | -AKC | -AMC'
     Specify which variant of the 960 architecture is the target.

`-b'
     Add code to collect statistics about branches taken.

`-no-relax'
     Do not alter compare-and-branch instructions for long
     displacements; error if necessary.


   The following options are available when as is configured for the
Ubicom IP2K series.

`-mip2022ext'
     Specifies that the extended IP2022 instructions are allowed.

`-mip2022'
     Restores the default behaviour, which restricts the permitted
     instructions to just the basic IP2022 ones.


   The following options are available when as is configured for the
Renesas M32C and M16C processors.

`-m32c'
     Assemble M32C instructions.

`-m16c'
     Assemble M16C instructions (the default).


   The following options are available when as is configured for the
Renesas M32R (formerly Mitsubishi M32R) series.

`--m32rx'
     Specify which processor in the M32R family is the target.  The
     default is normally the M32R, but this option changes it to the
     M32RX.

`--warn-explicit-parallel-conflicts or --Wp'
     Produce warning messages when questionable parallel constructs are
     encountered.

`--no-warn-explicit-parallel-conflicts or --Wnp'
     Do not produce warning messages when questionable parallel
     constructs are encountered.


   The following options are available when as is configured for the
Motorola 68000 series.

`-l'
     Shorten references to undefined symbols, to one word instead of
     two.

`-m68000 | -m68008 | -m68010 | -m68020 | -m68030'
`| -m68040 | -m68060 | -m68302 | -m68331 | -m68332'
`| -m68333 | -m68340 | -mcpu32 | -m5200'
     Specify what processor in the 68000 family is the target.  The
     default is normally the 68020, but this can be changed at
     configuration time.

`-m68881 | -m68882 | -mno-68881 | -mno-68882'
     The target machine does (or does not) have a floating-point
     coprocessor.  The default is to assume a coprocessor for 68020,
     68030, and cpu32.  Although the basic 68000 is not compatible with
     the 68881, a combination of the two can be specified, since it's
     possible to do emulation of the coprocessor instructions with the
     main processor.

`-m68851 | -mno-68851'
     The target machine does (or does not) have a memory-management
     unit coprocessor.  The default is to assume an MMU for 68020 and
     up.


   For details about the PDP-11 machine dependent features options, see
*Note PDP-11-Options::.

`-mpic | -mno-pic'
     Generate position-independent (or position-dependent) code.  The
     default is `-mpic'.

`-mall'
`-mall-extensions'
     Enable all instruction set extensions.  This is the default.

`-mno-extensions'
     Disable all instruction set extensions.

`-mEXTENSION | -mno-EXTENSION'
     Enable (or disable) a particular instruction set extension.

`-mCPU'
     Enable the instruction set extensions supported by a particular
     CPU, and disable all other extensions.

`-mMACHINE'
     Enable the instruction set extensions supported by a particular
     machine model, and disable all other extensions.

   The following options are available when as is configured for a
picoJava processor.

`-mb'
     Generate "big endian" format output.

`-ml'
     Generate "little endian" format output.


   The following options are available when as is configured for the
Motorola 68HC11 or 68HC12 series.

`-m68hc11 | -m68hc12 | -m68hcs12'
     Specify what processor is the target.  The default is defined by
     the configuration option when building the assembler.

`-mshort'
     Specify to use the 16-bit integer ABI.

`-mlong'
     Specify to use the 32-bit integer ABI.

`-mshort-double'
     Specify to use the 32-bit double ABI.

`-mlong-double'
     Specify to use the 64-bit double ABI.

`--force-long-branchs'
     Relative branches are turned into absolute ones. This concerns
     conditional branches, unconditional branches and branches to a sub
     routine.

`-S | --short-branchs'
     Do not turn relative branchs into absolute ones when the offset is
     out of range.

`--strict-direct-mode'
     Do not turn the direct addressing mode into extended addressing
     mode when the instruction does not support direct addressing mode.

`--print-insn-syntax'
     Print the syntax of instruction in case of error.

`--print-opcodes'
     print the list of instructions with syntax and then exit.

`--generate-example'
     print an example of instruction for each possible instruction and
     then exit.  This option is only useful for testing `as'.


   The following options are available when `as' is configured for the
SPARC architecture:

`-Av6 | -Av7 | -Av8 | -Asparclet | -Asparclite'
`-Av8plus | -Av8plusa | -Av9 | -Av9a'
     Explicitly select a variant of the SPARC architecture.

     `-Av8plus' and `-Av8plusa' select a 32 bit environment.  `-Av9'
     and `-Av9a' select a 64 bit environment.

     `-Av8plusa' and `-Av9a' enable the SPARC V9 instruction set with
     UltraSPARC extensions.

`-xarch=v8plus | -xarch=v8plusa'
     For compatibility with the Solaris v9 assembler.  These options are
     equivalent to -Av8plus and -Av8plusa, respectively.

`-bump'
     Warn when the assembler switches to another architecture.

   The following options are available when as is configured for the
'c54x architecture.

`-mfar-mode'
     Enable extended addressing mode.  All addresses and relocations
     will assume extended addressing (usually 23 bits).

`-mcpu=CPU_VERSION'
     Sets the CPU version being compiled for.

`-merrors-to-file FILENAME'
     Redirect error output to a file, for broken systems which don't
     support such behaviour in the shell.

   The following options are available when as is configured for a MIPS
processor.

`-G NUM'
     This option sets the largest size of an object that can be
     referenced implicitly with the `gp' register.  It is only accepted
     for targets that use ECOFF format, such as a DECstation running
     Ultrix.  The default value is 8.

`-EB'
     Generate "big endian" format output.

`-EL'
     Generate "little endian" format output.

`-mips1'
`-mips2'
`-mips3'
`-mips4'
`-mips5'
`-mips32'
`-mips32r2'
`-mips64'
`-mips64r2'
     Generate code for a particular MIPS Instruction Set Architecture
     level.  `-mips1' is an alias for `-march=r3000', `-mips2' is an
     alias for `-march=r6000', `-mips3' is an alias for `-march=r4000'
     and `-mips4' is an alias for `-march=r8000'.  `-mips5', `-mips32',
     `-mips32r2', `-mips64', and `-mips64r2' correspond to generic
     `MIPS V', `MIPS32', `MIPS32 Release 2', `MIPS64', and `MIPS64
     Release 2' ISA processors, respectively.

`-march=CPU'
     Generate code for a particular MIPS cpu.

`-mtune=CPU'
     Schedule and tune for a particular MIPS cpu.

`-mfix7000'
`-mno-fix7000'
     Cause nops to be inserted if the read of the destination register
     of an mfhi or mflo instruction occurs in the following two
     instructions.

`-mdebug'
`-no-mdebug'
     Cause stabs-style debugging output to go into an ECOFF-style
     .mdebug section instead of the standard ELF .stabs sections.

`-mpdr'
`-mno-pdr'
     Control generation of `.pdr' sections.

`-mgp32'
`-mfp32'
     The register sizes are normally inferred from the ISA and ABI, but
     these flags force a certain group of registers to be treated as 32
     bits wide at all times.  `-mgp32' controls the size of
     general-purpose registers and `-mfp32' controls the size of
     floating-point registers.

`-mips16'
`-no-mips16'
     Generate code for the MIPS 16 processor.  This is equivalent to
     putting `.set mips16' at the start of the assembly file.
     `-no-mips16' turns off this option.

`-mips3d'
`-no-mips3d'
     Generate code for the MIPS-3D Application Specific Extension.
     This tells the assembler to accept MIPS-3D instructions.
     `-no-mips3d' turns off this option.

`-mdmx'
`-no-mdmx'
     Generate code for the MDMX Application Specific Extension.  This
     tells the assembler to accept MDMX instructions.  `-no-mdmx' turns
     off this option.

`-mdsp'
`-mno-dsp'
     Generate code for the DSP Application Specific Extension.  This
     tells the assembler to accept DSP instructions.  `-mno-dsp' turns
     off this option.

`-mmt'
`-mno-mt'
     Generate code for the MT Application Specific Extension.  This
     tells the assembler to accept MT instructions.  `-mno-mt' turns
     off this option.

`--construct-floats'
`--no-construct-floats'
     The `--no-construct-floats' option disables the construction of
     double width floating point constants by loading the two halves of
     the value into the two single width floating point registers that
     make up the double width register.  By default
     `--construct-floats' is selected, allowing construction of these
     floating point constants.

`--emulation=NAME'
     This option causes `as' to emulate `as' configured for some other
     target, in all respects, including output format (choosing between
     ELF and ECOFF only), handling of pseudo-opcodes which may generate
     debugging information or store symbol table information, and
     default endianness.  The available configuration names are:
     `mipsecoff', `mipself', `mipslecoff', `mipsbecoff', `mipslelf',
     `mipsbelf'.  The first two do not alter the default endianness
     from that of the primary target for which the assembler was
     configured; the others change the default to little- or big-endian
     as indicated by the `b' or `l' in the name.  Using `-EB' or `-EL'
     will override the endianness selection in any case.

     This option is currently supported only when the primary target
     `as' is configured for is a MIPS ELF or ECOFF target.
     Furthermore, the primary target or others specified with
     `--enable-targets=...' at configuration time must include support
     for the other format, if both are to be available.  For example,
     the Irix 5 configuration includes support for both.

     Eventually, this option will support more configurations, with more
     fine-grained control over the assembler's behavior, and will be
     supported for more processors.

`-nocpp'
     `as' ignores this option.  It is accepted for compatibility with
     the native tools.

`--trap'
`--no-trap'
`--break'
`--no-break'
     Control how to deal with multiplication overflow and division by
     zero.  `--trap' or `--no-break' (which are synonyms) take a trap
     exception (and only work for Instruction Set Architecture level 2
     and higher); `--break' or `--no-trap' (also synonyms, and the
     default) take a break exception.

`-n'
     When this option is used, `as' will issue a warning every time it
     generates a nop instruction from a macro.

   The following options are available when as is configured for an
MCore processor.

`-jsri2bsr'
`-nojsri2bsr'
     Enable or disable the JSRI to BSR transformation.  By default this
     is enabled.  The command line option `-nojsri2bsr' can be used to
     disable it.

`-sifilter'
`-nosifilter'
     Enable or disable the silicon filter behaviour.  By default this
     is disabled.  The default can be overridden by the `-sifilter'
     command line option.

`-relax'
     Alter jump instructions for long displacements.

`-mcpu=[210|340]'
     Select the cpu type on the target hardware.  This controls which
     instructions can be assembled.

`-EB'
     Assemble for a big endian target.

`-EL'
     Assemble for a little endian target.


   See the info pages for documentation of the MMIX-specific options.

   The following options are available when as is configured for an
Xtensa processor.

`--text-section-literals | --no-text-section-literals'
     With `--text-section-literals', literal pools are interspersed in
     the text section.  The default is `--no-text-section-literals',
     which places literals in a separate section in the output file.
     These options only affect literals referenced via PC-relative
     `L32R' instructions; literals for absolute mode `L32R'
     instructions are handled separately.

`--absolute-literals | --no-absolute-literals'
     Indicate to the assembler whether `L32R' instructions use absolute
     or PC-relative addressing.  The default is to assume absolute
     addressing if the Xtensa processor includes the absolute `L32R'
     addressing option.  Otherwise, only the PC-relative `L32R' mode
     can be used.

`--target-align | --no-target-align'
     Enable or disable automatic alignment to reduce branch penalties
     at the expense of some code density.  The default is
     `--target-align'.

`--longcalls | --no-longcalls'
     Enable or disable transformation of call instructions to allow
     calls across a greater range of addresses.  The default is
     `--no-longcalls'.

`--transform | --no-transform'
     Enable or disable all assembler transformations of Xtensa
     instructions.  The default is `--transform'; `--no-transform'
     should be used only in the rare cases when the instructions must
     be exactly as specified in the assembly source.

   The following options are available when as is configured for a Z80
family processor.
`-z80'
     Assemble for Z80 processor.

`-r800'
     Assemble for R800 processor.

`-ignore-undocumented-instructions'
`-Wnud'
     Assemble undocumented Z80 instructions that also work on R800
     without warning.

`-ignore-unportable-instructions'
`-Wnup'
     Assemble all undocumented Z80 instructions without warning.

`-warn-undocumented-instructions'
`-Wud'
     Issue a warning for undocumented Z80 instructions that also work
     on R800.

`-warn-unportable-instructions'
`-Wup'
     Issue a warning for undocumented Z80 instructions that do notwork
     on R800.

`-forbid-undocumented-instructions'
`-Fud'
     Treat all undocumented instructions as errors.

`-forbid-unportable-instructions'
`-Fup'
     Treat undocumented Z80 intructions that do notwork on R800 as
     errors.

* Menu:

* Manual::                      Structure of this Manual
* GNU Assembler::               The GNU Assembler
* Object Formats::              Object File Formats
* Command Line::                Command Line
* Input Files::                 Input Files
* Object::                      Output (Object) File
* Errors::                      Error and Warning Messages


File: as.info,  Node: Manual,  Next: GNU Assembler,  Up: Overview

1.1 Structure of this Manual
============================

This manual is intended to describe what you need to know to use GNU
`as'.  We cover the syntax expected in source files, including notation
for symbols, constants, and expressions; the directives that `as'
understands; and of course how to invoke `as'.

   This manual also describes some of the machine-dependent features of
various flavors of the assembler.

   On the other hand, this manual is _not_ intended as an introduction
to programming in assembly language--let alone programming in general!
In a similar vein, we make no attempt to introduce the machine
architecture; we do _not_ describe the instruction set, standard
mnemonics, registers or addressing modes that are standard to a
particular architecture.  You may want to consult the manufacturer's
machine architecture manual for this information.


File: as.info,  Node: GNU Assembler,  Next: Object Formats,  Prev: Manual,  Up: Overview

1.2 The GNU Assembler
=====================

GNU `as' is really a family of assemblers.  If you use (or have used)
the GNU assembler on one architecture, you should find a fairly similar
environment when you use it on another architecture.  Each version has
much in common with the others, including object file formats, most
assembler directives (often called "pseudo-ops") and assembler syntax.

   `as' is primarily intended to assemble the output of the GNU C
compiler `gcc' for use by the linker `ld'.  Nevertheless, we've tried
to make `as' assemble correctly everything that other assemblers for
the same machine would assemble.  Any exceptions are documented
explicitly (*note Machine Dependencies::).  This doesn't mean `as'
always uses the same syntax as another assembler for the same
architecture; for example, we know of several incompatible versions of
680x0 assembly language syntax.

   Unlike older assemblers, `as' is designed to assemble a source
program in one pass of the source file.  This has a subtle impact on the
`.org' directive (*note `.org': Org.).


File: as.info,  Node: Object Formats,  Next: Command Line,  Prev: GNU Assembler,  Up: Overview

1.3 Object File Formats
=======================

The GNU assembler can be configured to produce several alternative
object file formats.  For the most part, this does not affect how you
write assembly language programs; but directives for debugging symbols
are typically different in different file formats.  *Note Symbol
Attributes: Symbol Attributes.


File: as.info,  Node: Command Line,  Next: Input Files,  Prev: Object Formats,  Up: Overview

1.4 Command Line
================

After the program name `as', the command line may contain options and
file names.  Options may appear in any order, and may be before, after,
or between file names.  The order of file names is significant.

   `--' (two hyphens) by itself names the standard input file
explicitly, as one of the files for `as' to assemble.

   Except for `--' any command line argument that begins with a hyphen
(`-') is an option.  Each option changes the behavior of `as'.  No
option changes the way another option works.  An option is a `-'
followed by one or more letters; the case of the letter is important.
All options are optional.

   Some options expect exactly one file name to follow them.  The file
name may either immediately follow the option's letter (compatible with
older assemblers) or it may be the next command argument (GNU
standard).  These two command lines are equivalent:

     as -o my-object-file.o mumble.s
     as -omy-object-file.o mumble.s


File: as.info,  Node: Input Files,  Next: Object,  Prev: Command Line,  Up: Overview

1.5 Input Files
===============

We use the phrase "source program", abbreviated "source", to describe
the program input to one run of `as'.  The program may be in one or
more files; how the source is partitioned into files doesn't change the
meaning of the source.

   The source program is a concatenation of the text in all the files,
in the order specified.

   Each time you run `as' it assembles exactly one source program.  The
source program is made up of one or more files.  (The standard input is
also a file.)

   You give `as' a command line that has zero or more input file names.
The input files are read (from left file name to right).  A command
line argument (in any position) that has no special meaning is taken to
be an input file name.

   If you give `as' no file names it attempts to read one input file
from the `as' standard input, which is normally your terminal.  You may
have to type <ctl-D> to tell `as' there is no more program to assemble.

   Use `--' if you need to explicitly name the standard input file in
your command line.

   If the source is empty, `as' produces a small, empty object file.

Filenames and Line-numbers
--------------------------

There are two ways of locating a line in the input file (or files) and
either may be used in reporting error messages.  One way refers to a
line number in a physical file; the other refers to a line number in a
"logical" file.  *Note Error and Warning Messages: Errors.

   "Physical files" are those files named in the command line given to
`as'.

   "Logical files" are simply names declared explicitly by assembler
directives; they bear no relation to physical files.  Logical file
names help error messages reflect the original source file, when `as'
source is itself synthesized from other files.  `as' understands the
`#' directives emitted by the `gcc' preprocessor.  See also *Note
`.file': File.


File: as.info,  Node: Object,  Next: Errors,  Prev: Input Files,  Up: Overview

1.6 Output (Object) File
========================

Every time you run `as' it produces an output file, which is your
assembly language program translated into numbers.  This file is the
object file.  Its default name is `a.out'.  You can give it another
name by using the `-o' option.  Conventionally, object file names end
with `.o'.  The default name is used for historical reasons: older
assemblers were capable of assembling self-contained programs directly
into a runnable program.  (For some formats, this isn't currently
possible, but it can be done for the `a.out' format.)

   The object file is meant for input to the linker `ld'.  It contains
assembled program code, information to help `ld' integrate the
assembled program into a runnable file, and (optionally) symbolic
information for the debugger.


File: as.info,  Node: Errors,  Prev: Object,  Up: Overview

1.7 Error and Warning Messages
==============================

`as' may write warnings and error messages to the standard error file
(usually your terminal).  This should not happen when  a compiler runs
`as' automatically.  Warnings report an assumption made so that `as'
could keep assembling a flawed program; errors report a grave problem
that stops the assembly.

   Warning messages have the format

     file_name:NNN:Warning Message Text

(where NNN is a line number).  If a logical file name has been given
(*note `.file': File.) it is used for the filename, otherwise the name
of the current input file is used.  If a logical line number was given
(*note `.line': Line.)  then it is used to calculate the number printed,
otherwise the actual line in the current source file is printed.  The
message text is intended to be self explanatory (in the grand Unix
tradition).

   Error messages have the format
     file_name:NNN:FATAL:Error Message Text
   The file name and line number are derived as for warning messages.
The actual message text may be rather less explanatory because many of
them aren't supposed to happen.


File: as.info,  Node: Invoking,  Next: Syntax,  Prev: Overview,  Up: Top

2 Command-Line Options
**********************

This chapter describes command-line options available in _all_ versions
of the GNU assembler; *note Machine Dependencies::, for options specific
to particular machine architectures.

   If you are invoking `as' via the GNU C compiler, you can use the
`-Wa' option to pass arguments through to the assembler.  The assembler
arguments must be separated from each other (and the `-Wa') by commas.
For example:

     gcc -c -g -O -Wa,-alh,-L file.c

This passes two options to the assembler: `-alh' (emit a listing to
standard output with high-level and assembly source) and `-L' (retain
local symbols in the symbol table).

   Usually you do not need to use this `-Wa' mechanism, since many
compiler command-line options are automatically passed to the assembler
by the compiler.  (You can call the GNU compiler driver with the `-v'
option to see precisely what options it passes to each compilation
pass, including the assembler.)

* Menu:

* a::             -a[cdhlns] enable listings
* alternate::     --alternate enable alternate macro syntax
* D::             -D for compatibility
* f::             -f to work faster
* I::             -I for .include search path

* K::             -K for difference tables

* L::             -L to retain local labels
* listing::       --listing-XXX to configure listing output
* M::		  -M or --mri to assemble in MRI compatibility mode
* MD::            --MD for dependency tracking
* o::             -o to name the object file
* R::             -R to join data and text sections
* statistics::    --statistics to see statistics about assembly
* traditional-format:: --traditional-format for compatible output
* v::             -v to announce version
* W::             -W, --no-warn, --warn, --fatal-warnings to control warnings
* Z::             -Z to make object file even after errors


File: as.info,  Node: a,  Next: alternate,  Up: Invoking

2.1 Enable Listings: `-a[cdhlns]'
=================================

These options enable listing output from the assembler.  By itself,
`-a' requests high-level, assembly, and symbols listing.  You can use
other letters to select specific options for the list: `-ah' requests a
high-level language listing, `-al' requests an output-program assembly
listing, and `-as' requests a symbol table listing.  High-level
listings require that a compiler debugging option like `-g' be used,
and that assembly listings (`-al') be requested also.

   Use the `-ac' option to omit false conditionals from a listing.  Any
lines which are not assembled because of a false `.if' (or `.ifdef', or
any other conditional), or a true `.if' followed by an `.else', will be
omitted from the listing.

   Use the `-ad' option to omit debugging directives from the listing.

   Once you have specified one of these options, you can further control
listing output and its appearance using the directives `.list',
`.nolist', `.psize', `.eject', `.title', and `.sbttl'.  The `-an'
option turns off all forms processing.  If you do not request listing
output with one of the `-a' options, the listing-control directives
have no effect.

   The letters after `-a' may be combined into one option, _e.g._,
`-aln'.

   Note if the assembler source is coming from the standard input (eg
because it is being created by `gcc' and the `-pipe' command line switch
is being used) then the listing will not contain any comments or
preprocessor directives.  This is because the listing code buffers
input source lines from stdin only after they have been preprocessed by
the assembler.  This reduces memory usage and makes the code more
efficient.


File: as.info,  Node: alternate,  Next: D,  Prev: a,  Up: Invoking

2.2 `--alternate'
=================

Begin in alternate macro mode, see *Note `.altmacro': Altmacro.


File: as.info,  Node: D,  Next: f,  Prev: alternate,  Up: Invoking

2.3 `-D'
========

This option has no effect whatsoever, but it is accepted to make it more
likely that scripts written for other assemblers also work with `as'.


File: as.info,  Node: f,  Next: I,  Prev: D,  Up: Invoking

2.4 Work Faster: `-f'
=====================

`-f' should only be used when assembling programs written by a
(trusted) compiler.  `-f' stops the assembler from doing whitespace and
comment preprocessing on the input file(s) before assembling them.
*Note Preprocessing: Preprocessing.

     _Warning:_ if you use `-f' when the files actually need to be
     preprocessed (if they contain comments, for example), `as' does
     not work correctly.


File: as.info,  Node: I,  Next: K,  Prev: f,  Up: Invoking

2.5 `.include' Search Path: `-I' PATH
=====================================

Use this option to add a PATH to the list of directories `as' searches
for files specified in `.include' directives (*note `.include':
Include.).  You may use `-I' as many times as necessary to include a
variety of paths.  The current working directory is always searched
first; after that, `as' searches any `-I' directories in the same order
as they were specified (left to right) on the command line.


File: as.info,  Node: K,  Next: L,  Prev: I,  Up: Invoking

2.6 Difference Tables: `-K'
===========================

`as' sometimes alters the code emitted for directives of the form
`.word SYM1-SYM2'; *note `.word': Word.  You can use the `-K' option if
you want a warning issued when this is done.


File: as.info,  Node: L,  Next: listing,  Prev: K,  Up: Invoking

2.7 Include Local Labels: `-L'
==============================

Labels beginning with `L' (upper case only) are called "local labels".
*Note Symbol Names::.  Normally you do not see such labels when
debugging, because they are intended for the use of programs (like
compilers) that compose assembler programs, not for your notice.
Normally both `as' and `ld' discard such labels, so you do not normally
debug with them.

   This option tells `as' to retain those `L...' symbols in the object
file.  Usually if you do this you also tell the linker `ld' to preserve
symbols whose names begin with `L'.

   By default, a local label is any label beginning with `L', but each
target is allowed to redefine the local label prefix.  On the HPPA
local labels begin with `L$'.


File: as.info,  Node: listing,  Next: M,  Prev: L,  Up: Invoking

2.8 Configuring listing output: `--listing'
===========================================

The listing feature of the assembler can be enabled via the command
line switch `-a' (*note a::).  This feature combines the input source
file(s) with a hex dump of the corresponding locations in the output
object file, and displays them as a listing file.  The format of this
listing can be controlled by pseudo ops inside the assembler source
(*note List:: *note Title:: *note Sbttl:: *note Psize:: *note Eject::)
and also by the following switches:

`--listing-lhs-width=`number''
     Sets the maximum width, in words, of the first line of the hex
     byte dump.  This dump appears on the left hand side of the listing
     output.

`--listing-lhs-width2=`number''
     Sets the maximum width, in words, of any further lines of the hex
     byte dump for a given input source line.  If this value is not
     specified, it defaults to being the same as the value specified
     for `--listing-lhs-width'.  If neither switch is used the default
     is to one.

`--listing-rhs-width=`number''
     Sets the maximum width, in characters, of the source line that is
     displayed alongside the hex dump.  The default value for this
     parameter is 100.  The source line is displayed on the right hand
     side of the listing output.

`--listing-cont-lines=`number''
     Sets the maximum number of continuation lines of hex dump that
     will be displayed for a given single line of source input.  The
     default value is 4.


File: as.info,  Node: M,  Next: MD,  Prev: listing,  Up: Invoking

2.9 Assemble in MRI Compatibility Mode: `-M'
============================================

The `-M' or `--mri' option selects MRI compatibility mode.  This
changes the syntax and pseudo-op handling of `as' to make it compatible
with the `ASM68K' or the `ASM960' (depending upon the configured
target) assembler from Microtec Research.  The exact nature of the MRI
syntax will not be documented here; see the MRI manuals for more
information.  Note in particular that the handling of macros and macro
arguments is somewhat different.  The purpose of this option is to
permit assembling existing MRI assembler code using `as'.

   The MRI compatibility is not complete.  Certain operations of the
MRI assembler depend upon its object file format, and can not be
supported using other object file formats.  Supporting these would
require enhancing each object file format individually.  These are:

   * global symbols in common section

     The m68k MRI assembler supports common sections which are merged
     by the linker.  Other object file formats do not support this.
     `as' handles common sections by treating them as a single common
     symbol.  It permits local symbols to be defined within a common
     section, but it can not support global symbols, since it has no
     way to describe them.

   * complex relocations

     The MRI assemblers support relocations against a negated section
     address, and relocations which combine the start addresses of two
     or more sections.  These are not support by other object file
     formats.

   * `END' pseudo-op specifying start address

     The MRI `END' pseudo-op permits the specification of a start
     address.  This is not supported by other object file formats.  The
     start address may instead be specified using the `-e' option to
     the linker, or in a linker script.

   * `IDNT', `.ident' and `NAME' pseudo-ops

     The MRI `IDNT', `.ident' and `NAME' pseudo-ops assign a module
     name to the output file.  This is not supported by other object
     file formats.

   * `ORG' pseudo-op

     The m68k MRI `ORG' pseudo-op begins an absolute section at a given
     address.  This differs from the usual `as' `.org' pseudo-op, which
     changes the location within the current section.  Absolute
     sections are not supported by other object file formats.  The
     address of a section may be assigned within a linker script.

   There are some other features of the MRI assembler which are not
supported by `as', typically either because they are difficult or
because they seem of little consequence.  Some of these may be
supported in future releases.

   * EBCDIC strings

     EBCDIC strings are not supported.

   * packed binary coded decimal

     Packed binary coded decimal is not supported.  This means that the
     `DC.P' and `DCB.P' pseudo-ops are not supported.

   * `FEQU' pseudo-op

     The m68k `FEQU' pseudo-op is not supported.

   * `NOOBJ' pseudo-op

     The m68k `NOOBJ' pseudo-op is not supported.

   * `OPT' branch control options

     The m68k `OPT' branch control options--`B', `BRS', `BRB', `BRL',
     and `BRW'--are ignored.  `as' automatically relaxes all branches,
     whether forward or backward, to an appropriate size, so these
     options serve no purpose.

   * `OPT' list control options

     The following m68k `OPT' list control options are ignored: `C',
     `CEX', `CL', `CRE', `E', `G', `I', `M', `MEX', `MC', `MD', `X'.

   * other `OPT' options

     The following m68k `OPT' options are ignored: `NEST', `O', `OLD',
     `OP', `P', `PCO', `PCR', `PCS', `R'.

   * `OPT' `D' option is default

     The m68k `OPT' `D' option is the default, unlike the MRI assembler.
     `OPT NOD' may be used to turn it off.

   * `XREF' pseudo-op.

     The m68k `XREF' pseudo-op is ignored.

   * `.debug' pseudo-op

     The i960 `.debug' pseudo-op is not supported.

   * `.extended' pseudo-op

     The i960 `.extended' pseudo-op is not supported.

   * `.list' pseudo-op.

     The various options of the i960 `.list' pseudo-op are not
     supported.

   * `.optimize' pseudo-op

     The i960 `.optimize' pseudo-op is not supported.

   * `.output' pseudo-op

     The i960 `.output' pseudo-op is not supported.

   * `.setreal' pseudo-op

     The i960 `.setreal' pseudo-op is not supported.



File: as.info,  Node: MD,  Next: o,  Prev: M,  Up: Invoking

2.10 Dependency Tracking: `--MD'
================================

`as' can generate a dependency file for the file it creates.  This file
consists of a single rule suitable for `make' describing the
dependencies of the main source file.

   The rule is written to the file named in its argument.

   This feature is used in the automatic updating of makefiles.


File: as.info,  Node: o,  Next: R,  Prev: MD,  Up: Invoking

2.11 Name the Object File: `-o'
===============================

There is always one object file output when you run `as'.  By default
it has the name `a.out' (or `b.out', for Intel 960 targets only).  You
use this option (which takes exactly one filename) to give the object
file a different name.

   Whatever the object file is called, `as' overwrites any existing
file of the same name.


File: as.info,  Node: R,  Next: statistics,  Prev: o,  Up: Invoking

2.12 Join Data and Text Sections: `-R'
======================================

`-R' tells `as' to write the object file as if all data-section data
lives in the text section.  This is only done at the very last moment:
your binary data are the same, but data section parts are relocated
differently.  The data section part of your object file is zero bytes
long because all its bytes are appended to the text section.  (*Note
Sections and Relocation: Sections.)

   When you specify `-R' it would be possible to generate shorter
address displacements (because we do not have to cross between text and
data section).  We refrain from doing this simply for compatibility with
older versions of `as'.  In future, `-R' may work this way.

   When `as' is configured for COFF or ELF output, this option is only
useful if you use sections named `.text' and `.data'.

   `-R' is not supported for any of the HPPA targets.  Using `-R'
generates a warning from `as'.


File: as.info,  Node: statistics,  Next: traditional-format,  Prev: R,  Up: Invoking

2.13 Display Assembly Statistics: `--statistics'
================================================

Use `--statistics' to display two statistics about the resources used by
`as': the maximum amount of space allocated during the assembly (in
bytes), and the total execution time taken for the assembly (in CPU
seconds).


File: as.info,  Node: traditional-format,  Next: v,  Prev: statistics,  Up: Invoking

2.14 Compatible Output: `--traditional-format'
==============================================

For some targets, the output of `as' is different in some ways from the
output of some existing assembler.  This switch requests `as' to use
the traditional format instead.

   For example, it disables the exception frame optimizations which
`as' normally does by default on `gcc' output.


File: as.info,  Node: v,  Next: W,  Prev: traditional-format,  Up: Invoking

2.15 Announce Version: `-v'
===========================

You can find out what version of as is running by including the option
`-v' (which you can also spell as `-version') on the command line.


File: as.info,  Node: W,  Next: Z,  Prev: v,  Up: Invoking

2.16 Control Warnings: `-W', `--warn', `--no-warn', `--fatal-warnings'
======================================================================

`as' should never give a warning or error message when assembling
compiler output.  But programs written by people often cause `as' to
give a warning that a particular assumption was made.  All such
warnings are directed to the standard error file.

   If you use the `-W' and `--no-warn' options, no warnings are issued.
This only affects the warning messages: it does not change any
particular of how `as' assembles your file.  Errors, which stop the
assembly, are still reported.

   If you use the `--fatal-warnings' option, `as' considers files that
generate warnings to be in error.

   You can switch these options off again by specifying `--warn', which
causes warnings to be output as usual.


File: as.info,  Node: Z,  Prev: W,  Up: Invoking

2.17 Generate Object File in Spite of Errors: `-Z'
==================================================

After an error message, `as' normally produces no output.  If for some
reason you are interested in object file output even after `as' gives
an error message on your program, use the `-Z' option.  If there are
any errors, `as' continues anyways, and writes an object file after a
final warning message of the form `N errors, M warnings, generating bad
object file.'


File: as.info,  Node: Syntax,  Next: Sections,  Prev: Invoking,  Up: Top

3 Syntax
********

This chapter describes the machine-independent syntax allowed in a
source file.  `as' syntax is similar to what many other assemblers use;
it is inspired by the BSD 4.2 assembler, except that `as' does not
assemble Vax bit-fields.

* Menu:

* Preprocessing::              Preprocessing
* Whitespace::                  Whitespace
* Comments::                    Comments
* Symbol Intro::                Symbols
* Statements::                  Statements
* Constants::                   Constants


File: as.info,  Node: Preprocessing,  Next: Whitespace,  Up: Syntax

3.1 Preprocessing
=================

The `as' internal preprocessor:
   * adjusts and removes extra whitespace.  It leaves one space or tab
     before the keywords on a line, and turns any other whitespace on
     the line into a single space.

   * removes all comments, replacing them with a single space, or an
     appropriate number of newlines.

   * converts character constants into the appropriate numeric values.

   It does not do macro processing, include file handling, or anything
else you may get from your C compiler's preprocessor.  You can do
include file processing with the `.include' directive (*note
`.include': Include.).  You can use the GNU C compiler driver to get
other "CPP" style preprocessing by giving the input file a `.S' suffix.
*Note Options Controlling the Kind of Output: (gcc.info)Overall
Options.

   Excess whitespace, comments, and character constants cannot be used
in the portions of the input text that are not preprocessed.

   If the first line of an input file is `#NO_APP' or if you use the
`-f' option, whitespace and comments are not removed from the input
file.  Within an input file, you can ask for whitespace and comment
removal in specific portions of the by putting a line that says `#APP'
before the text that may contain whitespace or comments, and putting a
line that says `#NO_APP' after this text.  This feature is mainly
intend to support `asm' statements in compilers whose output is
otherwise free of comments and whitespace.


File: as.info,  Node: Whitespace,  Next: Comments,  Prev: Preprocessing,  Up: Syntax

3.2 Whitespace
==============

"Whitespace" is one or more blanks or tabs, in any order.  Whitespace
is used to separate symbols, and to make programs neater for people to
read.  Unless within character constants (*note Character Constants:
Characters.), any whitespace means the same as exactly one space.


File: as.info,  Node: Comments,  Next: Symbol Intro,  Prev: Whitespace,  Up: Syntax

3.3 Comments
============

There are two ways of rendering comments to `as'.  In both cases the
comment is equivalent to one space.

   Anything from `/*' through the next `*/' is a comment.  This means
you may not nest these comments.

     /*
       The only way to include a newline ('\n') in a comment
       is to use this sort of comment.
     */

     /* This sort of comment does not nest. */

   Anything from the "line comment" character to the next newline is
considered a comment and is ignored.  The line comment character is `;'
on the ARC; `@' on the ARM; `;' for the H8/300 family; `;' for the HPPA;
`#' on the i386 and x86-64; `#' on the i960; `;' for the PDP-11; `;'
for picoJava; `#' for Motorola PowerPC; `!' for the Renesas / SuperH SH;
`!' on the SPARC; `#' on the ip2k; `#' on the m32c; `#' on the m32r;
`|' on the 680x0; `#' on the 68HC11 and 68HC12; `#' on the Vax; `;' for
the Z80; `!' for the Z8000; `#' on the V850; `#' for Xtensa systems;
see *Note Machine Dependencies::.

   On some machines there are two different line comment characters.
One character only begins a comment if it is the first non-whitespace
character on a line, while the other always begins a comment.

   The V850 assembler also supports a double dash as starting a comment
that extends to the end of the line.

   `--';

   To be compatible with past assemblers, lines that begin with `#'
have a special interpretation.  Following the `#' should be an absolute
expression (*note Expressions::): the logical line number of the _next_
line.  Then a string (*note Strings: Strings.) is allowed: if present
it is a new logical file name.  The rest of the line, if any, should be
whitespace.

   If the first non-whitespace characters on the line are not numeric,
the line is ignored.  (Just like a comment.)

                               # This is an ordinary comment.
     # 42-6 "new_file_name"    # New logical file name
                               # This is logical line # 36.
   This feature is deprecated, and may disappear from future versions
of `as'.


File: as.info,  Node: Symbol Intro,  Next: Statements,  Prev: Comments,  Up: Syntax

3.4 Symbols
===========

A "symbol" is one or more characters chosen from the set of all letters
(both upper and lower case), digits and the three characters `_.$'.  On
most machines, you can also use `$' in symbol names; exceptions are
noted in *Note Machine Dependencies::.  No symbol may begin with a
digit.  Case is significant.  There is no length limit: all characters
are significant.  Symbols are delimited by characters not in that set,
or by the beginning of a file (since the source program must end with a
newline, the end of a file is not a possible symbol delimiter).  *Note
Symbols::.  


File: as.info,  Node: Statements,  Next: Constants,  Prev: Symbol Intro,  Up: Syntax

3.5 Statements
==============

A "statement" ends at a newline character (`\n') or line separator
character.  (The line separator is usually `;', unless this conflicts
with the comment character; *note Machine Dependencies::.)  The newline
or separator character is considered part of the preceding statement.
Newlines and separators within character constants are an exception:
they do not end statements.

It is an error to end any statement with end-of-file:  the last
character of any input file should be a newline.

   An empty statement is allowed, and may include whitespace.  It is
ignored.

   A statement begins with zero or more labels, optionally followed by a
key symbol which determines what kind of statement it is.  The key
symbol determines the syntax of the rest of the statement.  If the
symbol begins with a dot `.' then the statement is an assembler
directive: typically valid for any computer.  If the symbol begins with
a letter the statement is an assembly language "instruction": it
assembles into a machine language instruction.  Different versions of
`as' for different computers recognize different instructions.  In
fact, the same symbol may represent a different instruction in a
different computer's assembly language.

   A label is a symbol immediately followed by a colon (`:').
Whitespace before a label or after a colon is permitted, but you may not
have whitespace between a label's symbol and its colon. *Note Labels::.

   For HPPA targets, labels need not be immediately followed by a
colon, but the definition of a label must begin in column zero.  This
also implies that only one label may be defined on each line.

     label:     .directive    followed by something
     another_label:           # This is an empty statement.
                instruction   operand_1, operand_2, ...


File: as.info,  Node: Constants,  Prev: Statements,  Up: Syntax

3.6 Constants
=============

A constant is a number, written so that its value is known by
inspection, without knowing any context.  Like this:
     .byte  74, 0112, 092, 0x4A, 0X4a, 'J, '\J # All the same value.
     .ascii "Ring the bell\7"                  # A string constant.
     .octa  0x123456789abcdef0123456789ABCDEF0 # A bignum.
     .float 0f-314159265358979323846264338327\
     95028841971.693993751E-40                 # - pi, a flonum.

* Menu:

* Characters::                  Character Constants
* Numbers::                     Number Constants


File: as.info,  Node: Characters,  Next: Numbers,  Up: Constants

3.6.1 Character Constants
-------------------------

There are two kinds of character constants.  A "character" stands for
one character in one byte and its value may be used in numeric
expressions.  String constants (properly called string _literals_) are
potentially many bytes and their values may not be used in arithmetic
expressions.

* Menu:

* Strings::                     Strings
* Chars::                       Characters


File: as.info,  Node: Strings,  Next: Chars,  Up: Characters

3.6.1.1 Strings
...............

A "string" is written between double-quotes.  It may contain
double-quotes or null characters.  The way to get special characters
into a string is to "escape" these characters: precede them with a
backslash `\' character.  For example `\\' represents one backslash:
the first `\' is an escape which tells `as' to interpret the second
character literally as a backslash (which prevents `as' from
recognizing the second `\' as an escape character).  The complete list
of escapes follows.

`\b'
     Mnemonic for backspace; for ASCII this is octal code 010.

`\f'
     Mnemonic for FormFeed; for ASCII this is octal code 014.

`\n'
     Mnemonic for newline; for ASCII this is octal code 012.

`\r'
     Mnemonic for carriage-Return; for ASCII this is octal code 015.

`\t'
     Mnemonic for horizontal Tab; for ASCII this is octal code 011.

`\ DIGIT DIGIT DIGIT'
     An octal character code.  The numeric code is 3 octal digits.  For
     compatibility with other Unix systems, 8 and 9 are accepted as
     digits: for example, `\008' has the value 010, and `\009' the
     value 011.

`\`x' HEX-DIGITS...'
     A hex character code.  All trailing hex digits are combined.
     Either upper or lower case `x' works.

`\\'
     Represents one `\' character.

`\"'
     Represents one `"' character.  Needed in strings to represent this
     character, because an unescaped `"' would end the string.

`\ ANYTHING-ELSE'
     Any other character when escaped by `\' gives a warning, but
     assembles as if the `\' was not present.  The idea is that if you
     used an escape sequence you clearly didn't want the literal
     interpretation of the following character.  However `as' has no
     other interpretation, so `as' knows it is giving you the wrong
     code and warns you of the fact.

   Which characters are escapable, and what those escapes represent,
varies widely among assemblers.  The current set is what we think the
BSD 4.2 assembler recognizes, and is a subset of what most C compilers
recognize.  If you are in doubt, do not use an escape sequence.


File: as.info,  Node: Chars,  Prev: Strings,  Up: Characters

3.6.1.2 Characters
..................

A single character may be written as a single quote immediately
followed by that character.  The same escapes apply to characters as to
strings.  So if you want to write the character backslash, you must
write `'\\' where the first `\' escapes the second `\'.  As you can
see, the quote is an acute accent, not a grave accent.  A newline
immediately following an acute accent is taken as a literal character
and does not count as the end of a statement.  The value of a character
constant in a numeric expression is the machine's byte-wide code for
that character.  `as' assumes your character code is ASCII: `'A' means
65, `'B' means 66, and so on.


File: as.info,  Node: Numbers,  Prev: Characters,  Up: Constants

3.6.2 Number Constants
----------------------

`as' distinguishes three kinds of numbers according to how they are
stored in the target machine.  _Integers_ are numbers that would fit
into an `int' in the C language.  _Bignums_ are integers, but they are
stored in more than 32 bits.  _Flonums_ are floating point numbers,
described below.

* Menu:

* Integers::                    Integers
* Bignums::                     Bignums
* Flonums::                     Flonums


File: as.info,  Node: Integers,  Next: Bignums,  Up: Numbers

3.6.2.1 Integers
................

A binary integer is `0b' or `0B' followed by zero or more of the binary
digits `01'.

   An octal integer is `0' followed by zero or more of the octal digits
(`01234567').

   A decimal integer starts with a non-zero digit followed by zero or
more digits (`0123456789').

   A hexadecimal integer is `0x' or `0X' followed by one or more
hexadecimal digits chosen from `0123456789abcdefABCDEF'.

   Integers have the usual values.  To denote a negative integer, use
the prefix operator `-' discussed under expressions (*note Prefix
Operators: Prefix Ops.).


File: as.info,  Node: Bignums,  Next: Flonums,  Prev: Integers,  Up: Numbers

3.6.2.2 Bignums
...............

A "bignum" has the same syntax and semantics as an integer except that
the number (or its negative) takes more than 32 bits to represent in
binary.  The distinction is made because in some places integers are
permitted while bignums are not.


File: as.info,  Node: Flonums,  Prev: Bignums,  Up: Numbers

3.6.2.3 Flonums
...............

A "flonum" represents a floating point number.  The translation is
indirect: a decimal floating point number from the text is converted by
`as' to a generic binary floating point number of more than sufficient
precision.  This generic floating point number is converted to a
particular computer's floating point format (or formats) by a portion
of `as' specialized to that computer.

   A flonum is written by writing (in order)
   * The digit `0'.  (`0' is optional on the HPPA.)

   * A letter, to tell `as' the rest of the number is a flonum.  `e' is
     recommended.  Case is not important.

     On the H8/300, Renesas / SuperH SH, and AMD 29K architectures, the
     letter must be one of the letters `DFPRSX' (in upper or lower
     case).

     On the ARC, the letter must be one of the letters `DFRS' (in upper
     or lower case).

     On the Intel 960 architecture, the letter must be one of the
     letters `DFT' (in upper or lower case).

     On the HPPA architecture, the letter must be `E' (upper case only).

   * An optional sign: either `+' or `-'.

   * An optional "integer part": zero or more decimal digits.

   * An optional "fractional part": `.' followed by zero or more
     decimal digits.

   * An optional exponent, consisting of:

        * An `E' or `e'.

        * Optional sign: either `+' or `-'.

        * One or more decimal digits.


   At least one of the integer part or the fractional part must be
present.  The floating point number has the usual base-10 value.

   `as' does all processing using integers.  Flonums are computed
independently of any floating point hardware in the computer running
`as'.


File: as.info,  Node: Sections,  Next: Symbols,  Prev: Syntax,  Up: Top

4 Sections and Relocation
*************************

* Menu:

* Secs Background::             Background
* Ld Sections::                 Linker Sections
* As Sections::                 Assembler Internal Sections
* Sub-Sections::                Sub-Sections
* bss::                         bss Section


File: as.info,  Node: Secs Background,  Next: Ld Sections,  Up: Sections

4.1 Background
==============

Roughly, a section is a range of addresses, with no gaps; all data "in"
those addresses is treated the same for some particular purpose.  For
example there may be a "read only" section.

   The linker `ld' reads many object files (partial programs) and
combines their contents to form a runnable program.  When `as' emits an
object file, the partial program is assumed to start at address 0.
`ld' assigns the final addresses for the partial program, so that
different partial programs do not overlap.  This is actually an
oversimplification, but it suffices to explain how `as' uses sections.

   `ld' moves blocks of bytes of your program to their run-time
addresses.  These blocks slide to their run-time addresses as rigid
units; their length does not change and neither does the order of bytes
within them.  Such a rigid unit is called a _section_.  Assigning
run-time addresses to sections is called "relocation".  It includes the
task of adjusting mentions of object-file addresses so they refer to
the proper run-time addresses.  For the H8/300, and for the Renesas /
SuperH SH, `as' pads sections if needed to ensure they end on a word
(sixteen bit) boundary.

   An object file written by `as' has at least three sections, any of
which may be empty.  These are named "text", "data" and "bss" sections.

   When it generates COFF or ELF output, `as' can also generate
whatever other named sections you specify using the `.section'
directive (*note `.section': Section.).  If you do not use any
directives that place output in the `.text' or `.data' sections, these
sections still exist, but are empty.

   When `as' generates SOM or ELF output for the HPPA, `as' can also
generate whatever other named sections you specify using the `.space'
and `.subspace' directives.  See `HP9000 Series 800 Assembly Language
Reference Manual' (HP 92432-90001) for details on the `.space' and
`.subspace' assembler directives.

   Additionally, `as' uses different names for the standard text, data,
and bss sections when generating SOM output.  Program text is placed
into the `$CODE$' section, data into `$DATA$', and BSS into `$BSS$'.

   Within the object file, the text section starts at address `0', the
data section follows, and the bss section follows the data section.

   When generating either SOM or ELF output files on the HPPA, the text
section starts at address `0', the data section at address `0x4000000',
and the bss section follows the data section.

   To let `ld' know which data changes when the sections are relocated,
and how to change that data, `as' also writes to the object file
details of the relocation needed.  To perform relocation `ld' must
know, each time an address in the object file is mentioned:
   * Where in the object file is the beginning of this reference to an
     address?

   * How long (in bytes) is this reference?

   * Which section does the address refer to?  What is the numeric
     value of
          (ADDRESS) - (START-ADDRESS OF SECTION)?

   * Is the reference to an address "Program-Counter relative"?

   In fact, every address `as' ever uses is expressed as
     (SECTION) + (OFFSET INTO SECTION)
   Further, most expressions `as' computes have this section-relative
nature.  (For some object formats, such as SOM for the HPPA, some
expressions are symbol-relative instead.)

   In this manual we use the notation {SECNAME N} to mean "offset N
into section SECNAME."

   Apart from text, data and bss sections you need to know about the
"absolute" section.  When `ld' mixes partial programs, addresses in the
absolute section remain unchanged.  For example, address `{absolute 0}'
is "relocated" to run-time address 0 by `ld'.  Although the linker
never arranges two partial programs' data sections with overlapping
addresses after linking, _by definition_ their absolute sections must
overlap.  Address `{absolute 239}' in one part of a program is always
the same address when the program is running as address `{absolute
239}' in any other part of the program.

   The idea of sections is extended to the "undefined" section.  Any
address whose section is unknown at assembly time is by definition
rendered {undefined U}--where U is filled in later.  Since numbers are
always defined, the only way to generate an undefined address is to
mention an undefined symbol.  A reference to a named common block would
be such a symbol: its value is unknown at assembly time so it has
section _undefined_.

   By analogy the word _section_ is used to describe groups of sections
in the linked program.  `ld' puts all partial programs' text sections
in contiguous addresses in the linked program.  It is customary to
refer to the _text section_ of a program, meaning all the addresses of
all partial programs' text sections.  Likewise for data and bss
sections.

   Some sections are manipulated by `ld'; others are invented for use
of `as' and have no meaning except during assembly.


File: as.info,  Node: Ld Sections,  Next: As Sections,  Prev: Secs Background,  Up: Sections

4.2 Linker Sections
===================

`ld' deals with just four kinds of sections, summarized below.

*named sections*
*text section*
*data section*
     These sections hold your program.  `as' and `ld' treat them as
     separate but equal sections.  Anything you can say of one section
     is true of another.  When the program is running, however, it is
     customary for the text section to be unalterable.  The text
     section is often shared among processes: it contains instructions,
     constants and the like.  The data section of a running program is
     usually alterable: for example, C variables would be stored in the
     data section.

*bss section*
     This section contains zeroed bytes when your program begins
     running.  It is used to hold uninitialized variables or common
     storage.  The length of each partial program's bss section is
     important, but because it starts out containing zeroed bytes there
     is no need to store explicit zero bytes in the object file.  The
     bss section was invented to eliminate those explicit zeros from
     object files.

*absolute section*
     Address 0 of this section is always "relocated" to runtime address
     0.  This is useful if you want to refer to an address that `ld'
     must not change when relocating.  In this sense we speak of
     absolute addresses being "unrelocatable": they do not change
     during relocation.

*undefined section*
     This "section" is a catch-all for address references to objects
     not in the preceding sections.

   An idealized example of three relocatable sections follows.  The
example uses the traditional section names `.text' and `.data'.  Memory
addresses are on the horizontal axis.

                           +-----+----+--+
     partial program # 1:  |ttttt|dddd|00|
                           +-----+----+--+

                           text   data bss
                           seg.   seg. seg.

                           +---+---+---+
     partial program # 2:  |TTT|DDD|000|
                           +---+---+---+

                           +--+---+-----+--+----+---+-----+~~
     linked program:       |  |TTT|ttttt|  |dddd|DDD|00000|
                           +--+---+-----+--+----+---+-----+~~

         addresses:        0 ...


File: as.info,  Node: As Sections,  Next: Sub-Sections,  Prev: Ld Sections,  Up: Sections

4.3 Assembler Internal Sections
===============================

These sections are meant only for the internal use of `as'.  They have
no meaning at run-time.  You do not really need to know about these
sections for most purposes; but they can be mentioned in `as' warning
messages, so it might be helpful to have an idea of their meanings to
`as'.  These sections are used to permit the value of every expression
in your assembly language program to be a section-relative address.

ASSEMBLER-INTERNAL-LOGIC-ERROR!
     An internal assembler logic error has been found.  This means
     there is a bug in the assembler.

expr section
     The assembler stores complex expression internally as combinations
     of symbols.  When it needs to represent an expression as a symbol,
     it puts it in the expr section.


File: as.info,  Node: Sub-Sections,  Next: bss,  Prev: As Sections,  Up: Sections

4.4 Sub-Sections
================

Assembled bytes conventionally fall into two sections: text and data.
You may have separate groups of data in named sections that you want to
end up near to each other in the object file, even though they are not
contiguous in the assembler source.  `as' allows you to use
"subsections" for this purpose.  Within each section, there can be
numbered subsections with values from 0 to 8192.  Objects assembled
into the same subsection go into the object file together with other
objects in the same subsection.  For example, a compiler might want to
store constants in the text section, but might not want to have them
interspersed with the program being assembled.  In this case, the
compiler could issue a `.text 0' before each section of code being
output, and a `.text 1' before each group of constants being output.

Subsections are optional.  If you do not use subsections, everything
goes in subsection number zero.

   Each subsection is zero-padded up to a multiple of four bytes.
(Subsections may be padded a different amount on different flavors of
`as'.)

   Subsections appear in your object file in numeric order, lowest
numbered to highest.  (All this to be compatible with other people's
assemblers.)  The object file contains no representation of
subsections; `ld' and other programs that manipulate object files see
no trace of them.  They just see all your text subsections as a text
section, and all your data subsections as a data section.

   To specify which subsection you want subsequent statements assembled
into, use a numeric argument to specify it, in a `.text EXPRESSION' or
a `.data EXPRESSION' statement.  When generating COFF output, you can
also use an extra subsection argument with arbitrary named sections:
`.section NAME, EXPRESSION'.  When generating ELF output, you can also
use the `.subsection' directive (*note SubSection::) to specify a
subsection: `.subsection EXPRESSION'.  EXPRESSION should be an absolute
expression.  (*Note Expressions::.)  If you just say `.text' then
`.text 0' is assumed.  Likewise `.data' means `.data 0'.  Assembly
begins in `text 0'.  For instance:
     .text 0     # The default subsection is text 0 anyway.
     .ascii "This lives in the first text subsection. *"
     .text 1
     .ascii "But this lives in the second text subsection."
     .data 0
     .ascii "This lives in the data section,"
     .ascii "in the first data subsection."
     .text 0
     .ascii "This lives in the first text section,"
     .ascii "immediately following the asterisk (*)."

   Each section has a "location counter" incremented by one for every
byte assembled into that section.  Because subsections are merely a
convenience restricted to `as' there is no concept of a subsection
location counter.  There is no way to directly manipulate a location
counter--but the `.align' directive changes it, and any label
definition captures its current value.  The location counter of the
section where statements are being assembled is said to be the "active"
location counter.


File: as.info,  Node: bss,  Prev: Sub-Sections,  Up: Sections

4.5 bss Section
===============

The bss section is used for local common variable storage.  You may
allocate address space in the bss section, but you may not dictate data
to load into it before your program executes.  When your program starts
running, all the contents of the bss section are zeroed bytes.

   The `.lcomm' pseudo-op defines a symbol in the bss section; see
*Note `.lcomm': Lcomm.

   The `.comm' pseudo-op may be used to declare a common symbol, which
is another form of uninitialized symbol; see *Note `.comm': Comm.

   When assembling for a target which supports multiple sections, such
as ELF or COFF, you may switch into the `.bss' section and define
symbols as usual; see *Note `.section': Section.  You may only assemble
zero values into the section.  Typically the section will only contain
symbol definitions and `.skip' directives (*note `.skip': Skip.).


File: as.info,  Node: Symbols,  Next: Expressions,  Prev: Sections,  Up: Top

5 Symbols
*********

Symbols are a central concept: the programmer uses symbols to name
things, the linker uses symbols to link, and the debugger uses symbols
to debug.

     _Warning:_ `as' does not place symbols in the object file in the
     same order they were declared.  This may break some debuggers.

* Menu:

* Labels::                      Labels
* Setting Symbols::             Giving Symbols Other Values
* Symbol Names::                Symbol Names
* Dot::                         The Special Dot Symbol
* Symbol Attributes::           Symbol Attributes


File: as.info,  Node: Labels,  Next: Setting Symbols,  Up: Symbols

5.1 Labels
==========

A "label" is written as a symbol immediately followed by a colon `:'.
The symbol then represents the current value of the active location
counter, and is, for example, a suitable instruction operand.  You are
warned if you use the same symbol to represent two different locations:
the first definition overrides any other definitions.

   On the HPPA, the usual form for a label need not be immediately
followed by a colon, but instead must start in column zero.  Only one
label may be defined on a single line.  To work around this, the HPPA
version of `as' also provides a special directive `.label' for defining
labels more flexibly.


File: as.info,  Node: Setting Symbols,  Next: Symbol Names,  Prev: Labels,  Up: Symbols

5.2 Giving Symbols Other Values
===============================

A symbol can be given an arbitrary value by writing a symbol, followed
by an equals sign `=', followed by an expression (*note Expressions::).
This is equivalent to using the `.set' directive.  *Note `.set': Set.
In the same way, using a double equals sign `='`=' here represents an
equivalent of the `.eqv' directive.  *Note `.eqv': Eqv.


File: as.info,  Node: Symbol Names,  Next: Dot,  Prev: Setting Symbols,  Up: Symbols

5.3 Symbol Names
================

Symbol names begin with a letter or with one of `._'.  On most
machines, you can also use `$' in symbol names; exceptions are noted in
*Note Machine Dependencies::.  That character may be followed by any
string of digits, letters, dollar signs (unless otherwise noted in
*Note Machine Dependencies::), and underscores.

Case of letters is significant: `foo' is a different symbol name than
`Foo'.

   Each symbol has exactly one name.  Each name in an assembly language
program refers to exactly one symbol.  You may use that symbol name any
number of times in a program.

Local Symbol Names
------------------

Local symbols help compilers and programmers use names temporarily.
They create symbols which are guaranteed to be unique over the entire
scope of the input source code and which can be referred to by a simple
notation.  To define a local symbol, write a label of the form `N:'
(where N represents any positive integer).  To refer to the most recent
previous definition of that symbol write `Nb', using the same number as
when you defined the label.  To refer to the next definition of a local
label, write `Nf'-- The `b' stands for"backwards" and the `f' stands
for "forwards".

   There is no restriction on how you can use these labels, and you can
reuse them too.  So that it is possible to repeatedly define the same
local label (using the same number `N'), although you can only refer to
the most recently defined local label of that number (for a backwards
reference) or the next definition of a specific local label for a
forward reference.  It is also worth noting that the first 10 local
labels (`0:'...`9:') are implemented in a slightly more efficient
manner than the others.

   Here is an example:

     1:        branch 1f
     2:        branch 1b
     1:        branch 2f
     2:        branch 1b

   Which is the equivalent of:

     label_1:  branch label_3
     label_2:  branch label_1
     label_3:  branch label_4
     label_4:  branch label_3

   Local symbol names are only a notational device.  They are
immediately transformed into more conventional symbol names before the
assembler uses them.  The symbol names stored in the symbol table,
appearing in error messages and optionally emitted to the object file.
The names are constructed using these parts:

`L'
     All local labels begin with `L'. Normally both `as' and `ld'
     forget symbols that start with `L'. These labels are used for
     symbols you are never intended to see.  If you use the `-L' option
     then `as' retains these symbols in the object file. If you also
     instruct `ld' to retain these symbols, you may use them in
     debugging.

`NUMBER'
     This is the number that was used in the local label definition.
     So if the label is written `55:' then the number is `55'.

`C-B'
     This unusual character is included so you do not accidentally
     invent a symbol of the same name.  The character has ASCII value
     of `\002' (control-B).

`_ordinal number_'
     This is a serial number to keep the labels distinct.  The first
     definition of `0:' gets the number `1'.  The 15th definition of
     `0:' gets the number `15', and so on.  Likewise the first
     definition of `1:' gets the number `1' and its 15th defintion gets
     `15' as well.

   So for example, the first `1:' is named `L1C-B1', the 44th `3:' is
named `L3C-B44'.

Dollar Local Labels
-------------------

`as' also supports an even more local form of local labels called
dollar labels.  These labels go out of scope (ie they become undefined)
as soon as a non-local label is defined.  Thus they remain valid for
only a small region of the input source code.  Normal local labels, by
contrast, remain in scope for the entire file, or until they are
redefined by another occurrence of the same local label.

   Dollar labels are defined in exactly the same way as ordinary local
labels, except that instead of being terminated by a colon, they are
terminated by a dollar sign.  eg `55$'.

   They can also be distinguished from ordinary local labels by their
transformed name which uses ASCII character `\001' (control-A) as the
magic character to distinguish them from ordinary labels.  Thus the 5th
defintion of `6$' is named `L6C-A5'.


File: as.info,  Node: Dot,  Next: Symbol Attributes,  Prev: Symbol Names,  Up: Symbols

5.4 The Special Dot Symbol
==========================

The special symbol `.' refers to the current address that `as' is
assembling into.  Thus, the expression `melvin: .long .' defines
`melvin' to contain its own address.  Assigning a value to `.' is
treated the same as a `.org' directive.  Thus, the expression `.=.+4'
is the same as saying `.space 4'.


File: as.info,  Node: Symbol Attributes,  Prev: Dot,  Up: Symbols

5.5 Symbol Attributes
=====================

Every symbol has, as well as its name, the attributes "Value" and
"Type".  Depending on output format, symbols can also have auxiliary
attributes.

   If you use a symbol without defining it, `as' assumes zero for all
these attributes, and probably won't warn you.  This makes the symbol
an externally defined symbol, which is generally what you would want.

* Menu:

* Symbol Value::                Value
* Symbol Type::                 Type


* a.out Symbols::               Symbol Attributes: `a.out'

* COFF Symbols::                Symbol Attributes for COFF

* SOM Symbols::                Symbol Attributes for SOM


File: as.info,  Node: Symbol Value,  Next: Symbol Type,  Up: Symbol Attributes

5.5.1 Value
-----------

The value of a symbol is (usually) 32 bits.  For a symbol which labels a
location in the text, data, bss or absolute sections the value is the
number of addresses from the start of that section to the label.
Naturally for text, data and bss sections the value of a symbol changes
as `ld' changes section base addresses during linking.  Absolute
symbols' values do not change during linking: that is why they are
called absolute.

   The value of an undefined symbol is treated in a special way.  If it
is 0 then the symbol is not defined in this assembler source file, and
`ld' tries to determine its value from other files linked into the same
program.  You make this kind of symbol simply by mentioning a symbol
name without defining it.  A non-zero value represents a `.comm' common
declaration.  The value is how much common storage to reserve, in bytes
(addresses).  The symbol refers to the first address of the allocated
storage.


File: as.info,  Node: Symbol Type,  Next: a.out Symbols,  Prev: Symbol Value,  Up: Symbol Attributes

5.5.2 Type
----------

The type attribute of a symbol contains relocation (section)
information, any flag settings indicating that a symbol is external, and
(optionally), other information for linkers and debuggers.  The exact
format depends on the object-code output format in use.


File: as.info,  Node: a.out Symbols,  Next: COFF Symbols,  Prev: Symbol Type,  Up: Symbol Attributes

5.5.3 Symbol Attributes: `a.out'
--------------------------------

* Menu:

* Symbol Desc::                 Descriptor
* Symbol Other::                Other


File: as.info,  Node: Symbol Desc,  Next: Symbol Other,  Up: a.out Symbols

5.5.3.1 Descriptor
..................

This is an arbitrary 16-bit value.  You may establish a symbol's
descriptor value by using a `.desc' statement (*note `.desc': Desc.).
A descriptor value means nothing to `as'.


File: as.info,  Node: Symbol Other,  Prev: Symbol Desc,  Up: a.out Symbols

5.5.3.2 Other
.............

This is an arbitrary 8-bit value.  It means nothing to `as'.


File: as.info,  Node: COFF Symbols,  Next: SOM Symbols,  Prev: a.out Symbols,  Up: Symbol Attributes

5.5.4 Symbol Attributes for COFF
--------------------------------

The COFF format supports a multitude of auxiliary symbol attributes;
like the primary symbol attributes, they are set between `.def' and
`.endef' directives.

5.5.4.1 Primary Attributes
..........................

The symbol name is set with `.def'; the value and type, respectively,
with `.val' and `.type'.

5.5.4.2 Auxiliary Attributes
............................

The `as' directives `.dim', `.line', `.scl', `.size', `.tag', and
`.weak' can generate auxiliary symbol table information for COFF.


File: as.info,  Node: SOM Symbols,  Prev: COFF Symbols,  Up: Symbol Attributes

5.5.5 Symbol Attributes for SOM
-------------------------------

The SOM format for the HPPA supports a multitude of symbol attributes
set with the `.EXPORT' and `.IMPORT' directives.

   The attributes are described in `HP9000 Series 800 Assembly Language
Reference Manual' (HP 92432-90001) under the `IMPORT' and `EXPORT'
assembler directive documentation.


File: as.info,  Node: Expressions,  Next: Pseudo Ops,  Prev: Symbols,  Up: Top

6 Expressions
*************

An "expression" specifies an address or numeric value.  Whitespace may
precede and/or follow an expression.

   The result of an expression must be an absolute number, or else an
offset into a particular section.  If an expression is not absolute,
and there is not enough information when `as' sees the expression to
know its section, a second pass over the source program might be
necessary to interpret the expression--but the second pass is currently
not implemented.  `as' aborts with an error message in this situation.

* Menu:

* Empty Exprs::                 Empty Expressions
* Integer Exprs::               Integer Expressions


File: as.info,  Node: Empty Exprs,  Next: Integer Exprs,  Up: Expressions

6.1 Empty Expressions
=====================

An empty expression has no value: it is just whitespace or null.
Wherever an absolute expression is required, you may omit the
expression, and `as' assumes a value of (absolute) 0.  This is
compatible with other assemblers.


File: as.info,  Node: Integer Exprs,  Prev: Empty Exprs,  Up: Expressions

6.2 Integer Expressions
=======================

An "integer expression" is one or more _arguments_ delimited by
_operators_.

* Menu:

* Arguments::                   Arguments
* Operators::                   Operators
* Prefix Ops::                  Prefix Operators
* Infix Ops::                   Infix Operators


File: as.info,  Node: Arguments,  Next: Operators,  Up: Integer Exprs

6.2.1 Arguments
---------------

"Arguments" are symbols, numbers or subexpressions.  In other contexts
arguments are sometimes called "arithmetic operands".  In this manual,
to avoid confusing them with the "instruction operands" of the machine
language, we use the term "argument" to refer to parts of expressions
only, reserving the word "operand" to refer only to machine instruction
operands.

   Symbols are evaluated to yield {SECTION NNN} where SECTION is one of
text, data, bss, absolute, or undefined.  NNN is a signed, 2's
complement 32 bit integer.

   Numbers are usually integers.

   A number can be a flonum or bignum.  In this case, you are warned
that only the low order 32 bits are used, and `as' pretends these 32
bits are an integer.  You may write integer-manipulating instructions
that act on exotic constants, compatible with other assemblers.

   Subexpressions are a left parenthesis `(' followed by an integer
expression, followed by a right parenthesis `)'; or a prefix operator
followed by an argument.


File: as.info,  Node: Operators,  Next: Prefix Ops,  Prev: Arguments,  Up: Integer Exprs

6.2.2 Operators
---------------

"Operators" are arithmetic functions, like `+' or `%'.  Prefix
operators are followed by an argument.  Infix operators appear between
their arguments.  Operators may be preceded and/or followed by
whitespace.


File: as.info,  Node: Prefix Ops,  Next: Infix Ops,  Prev: Operators,  Up: Integer Exprs

6.2.3 Prefix Operator
---------------------

`as' has the following "prefix operators".  They each take one
argument, which must be absolute.

`-'
     "Negation".  Two's complement negation.

`~'
     "Complementation".  Bitwise not.


File: as.info,  Node: Infix Ops,  Prev: Prefix Ops,  Up: Integer Exprs

6.2.4 Infix Operators
---------------------

"Infix operators" take two arguments, one on either side.  Operators
have precedence, but operations with equal precedence are performed left
to right.  Apart from `+' or `-', both arguments must be absolute, and
the result is absolute.

  1. Highest Precedence

    `*'
          "Multiplication".

    `/'
          "Division".  Truncation is the same as the C operator `/'

    `%'
          "Remainder".

    `<<'
          "Shift Left".  Same as the C operator `<<'.

    `>>'
          "Shift Right".  Same as the C operator `>>'.

  2. Intermediate precedence

    `|'
          "Bitwise Inclusive Or".

    `&'
          "Bitwise And".

    `^'
          "Bitwise Exclusive Or".

    `!'
          "Bitwise Or Not".

  3. Low Precedence

    `+'
          "Addition".  If either argument is absolute, the result has
          the section of the other argument.  You may not add together
          arguments from different sections.

    `-'
          "Subtraction".  If the right argument is absolute, the result
          has the section of the left argument.  If both arguments are
          in the same section, the result is absolute.  You may not
          subtract arguments from different sections.

    `=='
          "Is Equal To"

    `<>'
    `!='
          "Is Not Equal To"

    `<'
          "Is Less Than"

    `>'
          "Is Greater Than"

    `>='
          "Is Greater Than Or Equal To"

    `<='
          "Is Less Than Or Equal To"

          The comparison operators can be used as infix operators.  A
          true results has a value of -1 whereas a false result has a
          value of 0.   Note, these operators perform signed
          comparisons.

  4. Lowest Precedence

    `&&'
          "Logical And".

    `||'
          "Logical Or".

          These two logical operations can be used to combine the
          results of sub expressions.  Note, unlike the comparison
          operators a true result returns a value of 1 but a false
          results does still return 0.  Also note that the logical or
          operator has a slightly lower precedence than logical and.


   In short, it's only meaningful to add or subtract the _offsets_ in an
address; you can only have a defined section in one of the two
arguments.


File: as.info,  Node: Pseudo Ops,  Next: Machine Dependencies,  Prev: Expressions,  Up: Top

7 Assembler Directives
**********************

All assembler directives have names that begin with a period (`.').
The rest of the name is letters, usually in lower case.

   This chapter discusses directives that are available regardless of
the target machine configuration for the GNU assembler.  Some machine
configurations provide additional directives.  *Note Machine
Dependencies::.

* Menu:

* Abort::                       `.abort'

* ABORT::                       `.ABORT'

* Align::                       `.align ABS-EXPR , ABS-EXPR'
* Altmacro::                    `.altmacro'
* Ascii::                       `.ascii "STRING"'...
* Asciz::                       `.asciz "STRING"'...
* Balign::                      `.balign ABS-EXPR , ABS-EXPR'
* Byte::                        `.byte EXPRESSIONS'
* Comm::                        `.comm SYMBOL , LENGTH '

* CFI directives::		`.cfi_startproc', `.cfi_endproc', etc.

* Data::                        `.data SUBSECTION'

* Def::                         `.def NAME'

* Desc::                        `.desc SYMBOL, ABS-EXPRESSION'

* Dim::                         `.dim'

* Double::                      `.double FLONUMS'
* Eject::                       `.eject'
* Else::                        `.else'
* Elseif::                      `.elseif'
* End::				`.end'

* Endef::                       `.endef'

* Endfunc::                     `.endfunc'
* Endif::                       `.endif'
* Equ::                         `.equ SYMBOL, EXPRESSION'
* Equiv::                       `.equiv SYMBOL, EXPRESSION'
* Eqv::                         `.eqv SYMBOL, EXPRESSION'
* Err::				`.err'
* Error::			`.error STRING'
* Exitm::			`.exitm'
* Extern::                      `.extern'
* Fail::			`.fail'

* File::                        `.file STRING'

* Fill::                        `.fill REPEAT , SIZE , VALUE'
* Float::                       `.float FLONUMS'
* Func::                        `.func'
* Global::                      `.global SYMBOL', `.globl SYMBOL'

* Hidden::                      `.hidden NAMES'

* hword::                       `.hword EXPRESSIONS'
* Ident::                       `.ident'
* If::                          `.if ABSOLUTE EXPRESSION'
* Incbin::                      `.incbin "FILE"[,SKIP[,COUNT]]'
* Include::                     `.include "FILE"'
* Int::                         `.int EXPRESSIONS'

* Internal::                    `.internal NAMES'

* Irp::				`.irp SYMBOL,VALUES'...
* Irpc::			`.irpc SYMBOL,VALUES'...
* Lcomm::                       `.lcomm SYMBOL , LENGTH'
* Lflags::                      `.lflags'

* Line::                        `.line LINE-NUMBER'

* Linkonce::			`.linkonce [TYPE]'
* List::                        `.list'
* Ln::                          `.ln LINE-NUMBER'

* LNS directives::              `.file', `.loc', etc.

* Long::                        `.long EXPRESSIONS'

* Macro::			`.macro NAME ARGS'...
* MRI::				`.mri VAL'
* Noaltmacro::                  `.noaltmacro'
* Nolist::                      `.nolist'
* Octa::                        `.octa BIGNUMS'
* Org::                         `.org NEW-LC , FILL'
* P2align::                     `.p2align ABS-EXPR , ABS-EXPR'

* PopSection::                  `.popsection'
* Previous::                    `.previous'

* Print::			`.print STRING'

* Protected::                   `.protected NAMES'

* Psize::                       `.psize LINES, COLUMNS'
* Purgem::			`.purgem NAME'

* PushSection::                 `.pushsection NAME'

* Quad::                        `.quad BIGNUMS'
* Rept::			`.rept COUNT'
* Sbttl::                       `.sbttl "SUBHEADING"'

* Scl::                         `.scl CLASS'

* Section::                     `.section NAME'

* Set::                         `.set SYMBOL, EXPRESSION'
* Short::                       `.short EXPRESSIONS'
* Single::                      `.single FLONUMS'

* Size::                        `.size [NAME , EXPRESSION]'

* Skip::                        `.skip SIZE , FILL'
* Sleb128::			`.sleb128 EXPRESSIONS'
* Space::                       `.space SIZE , FILL'

* Stab::                        `.stabd, .stabn, .stabs'

* String::                      `.string "STR"'
* Struct::			`.struct EXPRESSION'

* SubSection::                  `.subsection'
* Symver::                      `.symver NAME,NAME2@NODENAME'


* Tag::                         `.tag STRUCTNAME'

* Text::                        `.text SUBSECTION'
* Title::                       `.title "HEADING"'

* Type::                        `.type <INT | NAME , TYPE DESCRIPTION>'

* Uleb128::                     `.uleb128 EXPRESSIONS'

* Val::                         `.val ADDR'


* Version::                     `.version "STRING"'
* VTableEntry::                 `.vtable_entry TABLE, OFFSET'
* VTableInherit::               `.vtable_inherit CHILD, PARENT'

* Warning::			`.warning STRING'
* Weak::                        `.weak NAMES'
* Weakref::                     `.weakref ALIAS, SYMBOL'
* Word::                        `.word EXPRESSIONS'
* Deprecated::                  Deprecated Directives


File: as.info,  Node: Abort,  Next: ABORT,  Up: Pseudo Ops

7.1 `.abort'
============

This directive stops the assembly immediately.  It is for compatibility
with other assemblers.  The original idea was that the assembly
language source would be piped into the assembler.  If the sender of
the source quit, it could use this directive tells `as' to quit also.
One day `.abort' will not be supported.


File: as.info,  Node: ABORT,  Next: Align,  Prev: Abort,  Up: Pseudo Ops

7.2 `.ABORT'
============

When producing COFF output, `as' accepts this directive as a synonym
for `.abort'.


File: as.info,  Node: Align,  Next: Altmacro,  Prev: ABORT,  Up: Pseudo Ops

7.3 `.align ABS-EXPR, ABS-EXPR, ABS-EXPR'
=========================================

Pad the location counter (in the current subsection) to a particular
storage boundary.  The first expression (which must be absolute) is the
alignment required, as described below.

   The second expression (also absolute) gives the fill value to be
stored in the padding bytes.  It (and the comma) may be omitted.  If it
is omitted, the padding bytes are normally zero.  However, on some
systems, if the section is marked as containing code and the fill value
is omitted, the space is filled with no-op instructions.

   The third expression is also absolute, and is also optional.  If it
is present, it is the maximum number of bytes that should be skipped by
this alignment directive.  If doing the alignment would require
skipping more bytes than the specified maximum, then the alignment is
not done at all.  You can omit the fill value (the second argument)
entirely by simply using two commas after the required alignment; this
can be useful if you want the alignment to be filled with no-op
instructions when appropriate.

   The way the required alignment is specified varies from system to
system.  For the arc, hppa, i386 using ELF, i860, iq2000, m68k, or32,
s390, sparc, tic4x, tic80 and xtensa, the first expression is the
alignment request in bytes.  For example `.align 8' advances the
location counter until it is a multiple of 8.  If the location counter
is already a multiple of 8, no change is needed.  For the tic54x, the
first expression is the alignment request in words.

   For other systems, including the i386 using a.out format, and the
arm and strongarm, it is the number of low-order zero bits the location
counter must have after advancement.  For example `.align 3' advances
the location counter until it a multiple of 8.  If the location counter
is already a multiple of 8, no change is needed.

   This inconsistency is due to the different behaviors of the various
native assemblers for these systems which GAS must emulate.  GAS also
provides `.balign' and `.p2align' directives, described later, which
have a consistent behavior across all architectures (but are specific
to GAS).


File: as.info,  Node: Ascii,  Next: Asciz,  Prev: Altmacro,  Up: Pseudo Ops

7.4 `.ascii "STRING"'...
========================

`.ascii' expects zero or more string literals (*note Strings::)
separated by commas.  It assembles each string (with no automatic
trailing zero byte) into consecutive addresses.


File: as.info,  Node: Asciz,  Next: Balign,  Prev: Ascii,  Up: Pseudo Ops

7.5 `.asciz "STRING"'...
========================

`.asciz' is just like `.ascii', but each string is followed by a zero
byte.  The "z" in `.asciz' stands for "zero".


File: as.info,  Node: Balign,  Next: Byte,  Prev: Asciz,  Up: Pseudo Ops

7.6 `.balign[wl] ABS-EXPR, ABS-EXPR, ABS-EXPR'
==============================================

Pad the location counter (in the current subsection) to a particular
storage boundary.  The first expression (which must be absolute) is the
alignment request in bytes.  For example `.balign 8' advances the
location counter until it is a multiple of 8.  If the location counter
is already a multiple of 8, no change is needed.

   The second expression (also absolute) gives the fill value to be
stored in the padding bytes.  It (and the comma) may be omitted.  If it
is omitted, the padding bytes are normally zero.  However, on some
systems, if the section is marked as containing code and the fill value
is omitted, the space is filled with no-op instructions.

   The third expression is also absolute, and is also optional.  If it
is present, it is the maximum number of bytes that should be skipped by
this alignment directive.  If doing the alignment would require
skipping more bytes than the specified maximum, then the alignment is
not done at all.  You can omit the fill value (the second argument)
entirely by simply using two commas after the required alignment; this
can be useful if you want the alignment to be filled with no-op
instructions when appropriate.

   The `.balignw' and `.balignl' directives are variants of the
`.balign' directive.  The `.balignw' directive treats the fill pattern
as a two byte word value.  The `.balignl' directives treats the fill
pattern as a four byte longword value.  For example, `.balignw
4,0x368d' will align to a multiple of 4.  If it skips two bytes, they
will be filled in with the value 0x368d (the exact placement of the
bytes depends upon the endianness of the processor).  If it skips 1 or
3 bytes, the fill value is undefined.


File: as.info,  Node: Byte,  Next: Comm,  Prev: Balign,  Up: Pseudo Ops

7.7 `.byte EXPRESSIONS'
=======================

`.byte' expects zero or more expressions, separated by commas.  Each
expression is assembled into the next byte.


File: as.info,  Node: Comm,  Next: CFI directives,  Prev: Byte,  Up: Pseudo Ops

7.8 `.comm SYMBOL , LENGTH '
============================

`.comm' declares a common symbol named SYMBOL.  When linking, a common
symbol in one object file may be merged with a defined or common symbol
of the same name in another object file.  If `ld' does not see a
definition for the symbol-just one or more common symbols-then it will
allocate LENGTH bytes of uninitialized memory.  LENGTH must be an
absolute expression.  If `ld' sees multiple common symbols with the
same name, and they do not all have the same size, it will allocate
space using the largest size.

   When using ELF, the `.comm' directive takes an optional third
argument.  This is the desired alignment of the symbol, specified as a
byte boundary (for example, an alignment of 16 means that the least
significant 4 bits of the address should be zero).  The alignment must
be an absolute expression, and it must be a power of two.  If `ld'
allocates uninitialized memory for the common symbol, it will use the
alignment when placing the symbol.  If no alignment is specified, `as'
will set the alignment to the largest power of two less than or equal
to the size of the symbol, up to a maximum of 16.

   The syntax for `.comm' differs slightly on the HPPA.  The syntax is
`SYMBOL .comm, LENGTH'; SYMBOL is optional.


File: as.info,  Node: CFI directives,  Next: Data,  Prev: Comm,  Up: Pseudo Ops

7.9 `.cfi_startproc'
====================

`.cfi_startproc' is used at the beginning of each function that should
have an entry in `.eh_frame'. It initializes some internal data
structures and emits architecture dependent initial CFI instructions.
Don't forget to close the function by `.cfi_endproc'.

7.10 `.cfi_endproc'
===================

`.cfi_endproc' is used at the end of a function where it closes its
unwind entry previously opened by `.cfi_startproc'. and emits it to
`.eh_frame'.

7.11 `.cfi_def_cfa REGISTER, OFFSET'
====================================

`.cfi_def_cfa' defines a rule for computing CFA as: take address from
REGISTER and add OFFSET to it.

7.12 `.cfi_def_cfa_register REGISTER'
=====================================

`.cfi_def_cfa_register' modifies a rule for computing CFA. From now on
REGISTER will be used instead of the old one. Offset remains the same.

7.13 `.cfi_def_cfa_offset OFFSET'
=================================

`.cfi_def_cfa_offset' modifies a rule for computing CFA. Register
remains the same, but OFFSET is new. Note that it is the absolute
offset that will be added to a defined register to compute CFA address.

7.14 `.cfi_adjust_cfa_offset OFFSET'
====================================

Same as `.cfi_def_cfa_offset' but OFFSET is a relative value that is
added/substracted from the previous offset.

7.15 `.cfi_offset REGISTER, OFFSET'
===================================

Previous value of REGISTER is saved at offset OFFSET from CFA.

7.16 `.cfi_rel_offset REGISTER, OFFSET'
=======================================

Previous value of REGISTER is saved at offset OFFSET from the current
CFA register.  This is transformed to `.cfi_offset' using the known
displacement of the CFA register from the CFA.  This is often easier to
use, because the number will match the code it's annotating.

7.17 `.cfi_signal_frame'
========================

Mark current function as signal trampoline.

7.18 `.cfi_window_save'
=======================

SPARC register window has been saved.

7.19 `.cfi_escape' EXPRESSION[, ...]
====================================

Allows the user to add arbitrary bytes to the unwind info.  One might
use this to add OS-specific CFI opcodes, or generic CFI opcodes that
GAS does not yet support.


File: as.info,  Node: LNS directives,  Next: Long,  Prev: Ln,  Up: Pseudo Ops

7.20 `.file FILENO FILENAME'
============================

When emitting dwarf2 line number information `.file' assigns filenames
to the `.debug_line' file name table.  The FILENO operand should be a
unique positive integer to use as the index of the entry in the table.
The FILENAME operand is a C string literal.

   The detail of filename indicies is exposed to the user because the
filename table is shared with the `.debug_info' section of the dwarf2
debugging information, and thus the user must know the exact indicies
that table entries will have.

7.21 `.loc FILENO LINENO [COLUMN] [OPTIONS]'
============================================

The `.loc' directive will add row to the `.debug_line' line number
matrix corresponding to the immediately following assembly instruction.
The FILENO, LINENO, and optional COLUMN arguments will be applied to
the `.debug_line' state machine before the row is added.

   The OPTIONS are a sequence of the following tokens in any order:

`basic_block'
     This option will set the `basic_block' register in the
     `.debug_line' state machine to `true'.

`prologue_end'
     This option will set the `prologue_end' register in the
     `.debug_line' state machine to `true'.

`epilogue_begin'
     This option will set the `epilogue_begin' register in the
     `.debug_line' state machine to `true'.

`is_stmt VALUE'
     This option will set the `is_stmt' register in the `.debug_line'
     state machine to `value', which must be either 0 or 1.

`isa VALUE'
     This directive will set the `isa' register in the `.debug_line'
     state machine to VALUE, which must be an unsigned integer.


7.22 `.loc_mark_blocks ENABLE'
==============================

The `.loc_mark_blocks' directive makes the assembler emit an entry to
the `.debug_line' line number matrix with the `basic_block' register in
the state machine set whenever a code label is seen.  The ENABLE
argument should be either 1 or 0, to enable or disable this function
respectively.


File: as.info,  Node: Data,  Next: Def,  Prev: CFI directives,  Up: Pseudo Ops

7.23 `.data SUBSECTION'
=======================

`.data' tells `as' to assemble the following statements onto the end of
the data subsection numbered SUBSECTION (which is an absolute
expression).  If SUBSECTION is omitted, it defaults to zero.


File: as.info,  Node: Def,  Next: Desc,  Prev: Data,  Up: Pseudo Ops

7.24 `.def NAME'
================

Begin defining debugging information for a symbol NAME; the definition
extends until the `.endef' directive is encountered.


File: as.info,  Node: Desc,  Next: Dim,  Prev: Def,  Up: Pseudo Ops

7.25 `.desc SYMBOL, ABS-EXPRESSION'
===================================

This directive sets the descriptor of the symbol (*note Symbol
Attributes::) to the low 16 bits of an absolute expression.

   The `.desc' directive is not available when `as' is configured for
COFF output; it is only for `a.out' or `b.out' object format.  For the
sake of compatibility, `as' accepts it, but produces no output, when
configured for COFF.


File: as.info,  Node: Dim,  Next: Double,  Prev: Desc,  Up: Pseudo Ops

7.26 `.dim'
===========

This directive is generated by compilers to include auxiliary debugging
information in the symbol table.  It is only permitted inside
`.def'/`.endef' pairs.


File: as.info,  Node: Double,  Next: Eject,  Prev: Dim,  Up: Pseudo Ops

7.27 `.double FLONUMS'
======================

`.double' expects zero or more flonums, separated by commas.  It
assembles floating point numbers.  The exact kind of floating point
numbers emitted depends on how `as' is configured.  *Note Machine
Dependencies::.


File: as.info,  Node: Eject,  Next: Else,  Prev: Double,  Up: Pseudo Ops

7.28 `.eject'
=============

Force a page break at this point, when generating assembly listings.


File: as.info,  Node: Else,  Next: Elseif,  Prev: Eject,  Up: Pseudo Ops

7.29 `.else'
============

`.else' is part of the `as' support for conditional assembly; *note
`.if': If.  It marks the beginning of a section of code to be assembled
if the condition for the preceding `.if' was false.


File: as.info,  Node: Elseif,  Next: End,  Prev: Else,  Up: Pseudo Ops

7.30 `.elseif'
==============

`.elseif' is part of the `as' support for conditional assembly; *note
`.if': If.  It is shorthand for beginning a new `.if' block that would
otherwise fill the entire `.else' section.


File: as.info,  Node: End,  Next: Endef,  Prev: Elseif,  Up: Pseudo Ops

7.31 `.end'
===========

`.end' marks the end of the assembly file.  `as' does not process
anything in the file past the `.end' directive.


File: as.info,  Node: Endef,  Next: Endfunc,  Prev: End,  Up: Pseudo Ops

7.32 `.endef'
=============

This directive flags the end of a symbol definition begun with `.def'.


File: as.info,  Node: Endfunc,  Next: Endif,  Prev: Endef,  Up: Pseudo Ops

7.33 `.endfunc'
===============

`.endfunc' marks the end of a function specified with `.func'.


File: as.info,  Node: Endif,  Next: Equ,  Prev: Endfunc,  Up: Pseudo Ops

7.34 `.endif'
=============

`.endif' is part of the `as' support for conditional assembly; it marks
the end of a block of code that is only assembled conditionally.  *Note
`.if': If.


File: as.info,  Node: Equ,  Next: Equiv,  Prev: Endif,  Up: Pseudo Ops

7.35 `.equ SYMBOL, EXPRESSION'
==============================

This directive sets the value of SYMBOL to EXPRESSION.  It is
synonymous with `.set'; *note `.set': Set.

   The syntax for `equ' on the HPPA is `SYMBOL .equ EXPRESSION'.

   The syntax for `equ' on the Z80 is `SYMBOL equ EXPRESSION'.  On the
Z80 it is an eror if SYMBOL is already defined, but the symbol is not
protected from later redefinition, compare *Note Equiv::.


File: as.info,  Node: Equiv,  Next: Eqv,  Prev: Equ,  Up: Pseudo Ops

7.36 `.equiv SYMBOL, EXPRESSION'
================================

The `.equiv' directive is like `.equ' and `.set', except that the
assembler will signal an error if SYMBOL is already defined.  Note a
symbol which has been referenced but not actually defined is considered
to be undefined.

   Except for the contents of the error message, this is roughly
equivalent to
     .ifdef SYM
     .err
     .endif
     .equ SYM,VAL
   plus it protects the symbol from later redefinition.


File: as.info,  Node: Eqv,  Next: Err,  Prev: Equiv,  Up: Pseudo Ops

7.37 `.eqv SYMBOL, EXPRESSION'
==============================

The `.eqv' directive is like `.equiv', but no attempt is made to
evaluate the expression or any part of it immediately.  Instead each
time the resulting symbol is used in an expression, a snapshot of its
current value is taken.


File: as.info,  Node: Err,  Next: Error,  Prev: Eqv,  Up: Pseudo Ops

7.38 `.err'
===========

If `as' assembles a `.err' directive, it will print an error message
and, unless the `-Z' option was used, it will not generate an object
file.  This can be used to signal an error in conditionally compiled
code.


File: as.info,  Node: Error,  Next: Exitm,  Prev: Err,  Up: Pseudo Ops

7.39 `.error "STRING"'
======================

Similarly to `.err', this directive emits an error, but you can specify
a string that will be emitted as the error message.  If you don't
specify the message, it defaults to `".error directive invoked in
source file"'.  *Note Error and Warning Messages: Errors.

      .error "This code has not been assembled and tested."


File: as.info,  Node: Exitm,  Next: Extern,  Prev: Error,  Up: Pseudo Ops

7.40 `.exitm'
=============

Exit early from the current macro definition.  *Note Macro::.


File: as.info,  Node: Extern,  Next: Fail,  Prev: Exitm,  Up: Pseudo Ops

7.41 `.extern'
==============

`.extern' is accepted in the source program--for compatibility with
other assemblers--but it is ignored.  `as' treats all undefined symbols
as external.


File: as.info,  Node: Fail,  Next: File,  Prev: Extern,  Up: Pseudo Ops

7.42 `.fail EXPRESSION'
=======================

Generates an error or a warning.  If the value of the EXPRESSION is 500
or more, `as' will print a warning message.  If the value is less than
500, `as' will print an error message.  The message will include the
value of EXPRESSION.  This can occasionally be useful inside complex
nested macros or conditional assembly.


File: as.info,  Node: File,  Next: Fill,  Prev: Fail,  Up: Pseudo Ops

7.43 `.file STRING'
===================

`.file' tells `as' that we are about to start a new logical file.
STRING is the new file name.  In general, the filename is recognized
whether or not it is surrounded by quotes `"'; but if you wish to
specify an empty file name, you must give the quotes-`""'.  This
statement may go away in future: it is only recognized to be compatible
with old `as' programs.


File: as.info,  Node: Fill,  Next: Float,  Prev: File,  Up: Pseudo Ops

7.44 `.fill REPEAT , SIZE , VALUE'
==================================

REPEAT, SIZE and VALUE are absolute expressions.  This emits REPEAT
copies of SIZE bytes.  REPEAT may be zero or more.  SIZE may be zero or
more, but if it is more than 8, then it is deemed to have the value 8,
compatible with other people's assemblers.  The contents of each REPEAT
bytes is taken from an 8-byte number.  The highest order 4 bytes are
zero.  The lowest order 4 bytes are VALUE rendered in the byte-order of
an integer on the computer `as' is assembling for.  Each SIZE bytes in
a repetition is taken from the lowest order SIZE bytes of this number.
Again, this bizarre behavior is compatible with other people's
assemblers.

   SIZE and VALUE are optional.  If the second comma and VALUE are
absent, VALUE is assumed zero.  If the first comma and following tokens
are absent, SIZE is assumed to be 1.


File: as.info,  Node: Float,  Next: Func,  Prev: Fill,  Up: Pseudo Ops

7.45 `.float FLONUMS'
=====================

This directive assembles zero or more flonums, separated by commas.  It
has the same effect as `.single'.  The exact kind of floating point
numbers emitted depends on how `as' is configured.  *Note Machine
Dependencies::.


File: as.info,  Node: Func,  Next: Global,  Prev: Float,  Up: Pseudo Ops

7.46 `.func NAME[,LABEL]'
=========================

`.func' emits debugging information to denote function NAME, and is
ignored unless the file is assembled with debugging enabled.  Only
`--gstabs[+]' is currently supported.  LABEL is the entry point of the
function and if omitted NAME prepended with the `leading char' is used.
`leading char' is usually `_' or nothing, depending on the target.  All
functions are currently defined to have `void' return type.  The
function must be terminated with `.endfunc'.


File: as.info,  Node: Global,  Next: Hidden,  Prev: Func,  Up: Pseudo Ops

7.47 `.global SYMBOL', `.globl SYMBOL'
======================================

`.global' makes the symbol visible to `ld'.  If you define SYMBOL in
your partial program, its value is made available to other partial
programs that are linked with it.  Otherwise, SYMBOL takes its
attributes from a symbol of the same name from another file linked into
the same program.

   Both spellings (`.globl' and `.global') are accepted, for
compatibility with other assemblers.

   On the HPPA, `.global' is not always enough to make it accessible to
other partial programs.  You may need the HPPA-only `.EXPORT' directive
as well.  *Note HPPA Assembler Directives: HPPA Directives.


File: as.info,  Node: Hidden,  Next: hword,  Prev: Global,  Up: Pseudo Ops

7.48 `.hidden NAMES'
====================

This is one of the ELF visibility directives.  The other two are
`.internal' (*note `.internal': Internal.) and `.protected' (*note
`.protected': Protected.).

   This directive overrides the named symbols default visibility (which
is set by their binding: local, global or weak).  The directive sets
the visibility to `hidden' which means that the symbols are not visible
to other components.  Such symbols are always considered to be
`protected' as well.


File: as.info,  Node: hword,  Next: Ident,  Prev: Hidden,  Up: Pseudo Ops

7.49 `.hword EXPRESSIONS'
=========================

This expects zero or more EXPRESSIONS, and emits a 16 bit number for
each.

   This directive is a synonym for `.short'; depending on the target
architecture, it may also be a synonym for `.word'.


File: as.info,  Node: Ident,  Next: If,  Prev: hword,  Up: Pseudo Ops

7.50 `.ident'
=============

This directive is used by some assemblers to place tags in object
files.  The behavior of this directive varies depending on the target.
When using the a.out object file format, `as' simply accepts the
directive for source-file compatibility with existing assemblers, but
does not emit anything for it.  When using COFF, comments are emitted
to the `.comment' or `.rdata' section, depending on the target.  When
using ELF, comments are emitted to the `.comment' section.


File: as.info,  Node: If,  Next: Incbin,  Prev: Ident,  Up: Pseudo Ops

7.51 `.if ABSOLUTE EXPRESSION'
==============================

`.if' marks the beginning of a section of code which is only considered
part of the source program being assembled if the argument (which must
be an ABSOLUTE EXPRESSION) is non-zero.  The end of the conditional
section of code must be marked by `.endif' (*note `.endif': Endif.);
optionally, you may include code for the alternative condition, flagged
by `.else' (*note `.else': Else.).  If you have several conditions to
check, `.elseif' may be used to avoid nesting blocks if/else within
each subsequent `.else' block.

   The following variants of `.if' are also supported:
`.ifdef SYMBOL'
     Assembles the following section of code if the specified SYMBOL
     has been defined.  Note a symbol which has been referenced but not
     yet defined is considered to be undefined.

`.ifb TEXT'
     Assembles the following section of code if the operand is blank
     (empty).

`.ifc STRING1,STRING2'
     Assembles the following section of code if the two strings are the
     same.  The strings may be optionally quoted with single quotes.
     If they are not quoted, the first string stops at the first comma,
     and the second string stops at the end of the line.  Strings which
     contain whitespace should be quoted.  The string comparison is
     case sensitive.

`.ifeq ABSOLUTE EXPRESSION'
     Assembles the following section of code if the argument is zero.

`.ifeqs STRING1,STRING2'
     Another form of `.ifc'.  The strings must be quoted using double
     quotes.

`.ifge ABSOLUTE EXPRESSION'
     Assembles the following section of code if the argument is greater
     than or equal to zero.

`.ifgt ABSOLUTE EXPRESSION'
     Assembles the following section of code if the argument is greater
     than zero.

`.ifle ABSOLUTE EXPRESSION'
     Assembles the following section of code if the argument is less
     than or equal to zero.

`.iflt ABSOLUTE EXPRESSION'
     Assembles the following section of code if the argument is less
     than zero.

`.ifnb TEXT'
     Like `.ifb', but the sense of the test is reversed: this assembles
     the following section of code if the operand is non-blank
     (non-empty).

`.ifnc STRING1,STRING2.'
     Like `.ifc', but the sense of the test is reversed: this assembles
     the following section of code if the two strings are not the same.

`.ifndef SYMBOL'
`.ifnotdef SYMBOL'
     Assembles the following section of code if the specified SYMBOL
     has not been defined.  Both spelling variants are equivalent.
     Note a symbol which has been referenced but not yet defined is
     considered to be undefined.

`.ifne ABSOLUTE EXPRESSION'
     Assembles the following section of code if the argument is not
     equal to zero (in other words, this is equivalent to `.if').

`.ifnes STRING1,STRING2'
     Like `.ifeqs', but the sense of the test is reversed: this
     assembles the following section of code if the two strings are not
     the same.


File: as.info,  Node: Incbin,  Next: Include,  Prev: If,  Up: Pseudo Ops

7.52 `.incbin "FILE"[,SKIP[,COUNT]]'
====================================

The `incbin' directive includes FILE verbatim at the current location.
You can control the search paths used with the `-I' command-line option
(*note Command-Line Options: Invoking.).  Quotation marks are required
around FILE.

   The SKIP argument skips a number of bytes from the start of the
FILE.  The COUNT argument indicates the maximum number of bytes to
read.  Note that the data is not aligned in any way, so it is the user's
responsibility to make sure that proper alignment is provided both
before and after the `incbin' directive.


File: as.info,  Node: Include,  Next: Int,  Prev: Incbin,  Up: Pseudo Ops

7.53 `.include "FILE"'
======================

This directive provides a way to include supporting files at specified
points in your source program.  The code from FILE is assembled as if
it followed the point of the `.include'; when the end of the included
file is reached, assembly of the original file continues.  You can
control the search paths used with the `-I' command-line option (*note
Command-Line Options: Invoking.).  Quotation marks are required around
FILE.


File: as.info,  Node: Int,  Next: Internal,  Prev: Include,  Up: Pseudo Ops

7.54 `.int EXPRESSIONS'
=======================

Expect zero or more EXPRESSIONS, of any section, separated by commas.
For each expression, emit a number that, at run time, is the value of
that expression.  The byte order and bit size of the number depends on
what kind of target the assembly is for.


File: as.info,  Node: Internal,  Next: Irp,  Prev: Int,  Up: Pseudo Ops

7.55 `.internal NAMES'
======================

This is one of the ELF visibility directives.  The other two are
`.hidden' (*note `.hidden': Hidden.) and `.protected' (*note
`.protected': Protected.).

   This directive overrides the named symbols default visibility (which
is set by their binding: local, global or weak).  The directive sets
the visibility to `internal' which means that the symbols are
considered to be `hidden' (i.e., not visible to other components), and
that some extra, processor specific processing must also be performed
upon the  symbols as well.


File: as.info,  Node: Irp,  Next: Irpc,  Prev: Internal,  Up: Pseudo Ops

7.56 `.irp SYMBOL,VALUES'...
============================

Evaluate a sequence of statements assigning different values to SYMBOL.
The sequence of statements starts at the `.irp' directive, and is
terminated by an `.endr' directive.  For each VALUE, SYMBOL is set to
VALUE, and the sequence of statements is assembled.  If no VALUE is
listed, the sequence of statements is assembled once, with SYMBOL set
to the null string.  To refer to SYMBOL within the sequence of
statements, use \SYMBOL.

   For example, assembling

             .irp    param,1,2,3
             move    d\param,sp@-
             .endr

   is equivalent to assembling

             move    d1,sp@-
             move    d2,sp@-
             move    d3,sp@-

   For some caveats with the spelling of SYMBOL, see also the discussion
at *Note Macro::.


File: as.info,  Node: Irpc,  Next: Lcomm,  Prev: Irp,  Up: Pseudo Ops

7.57 `.irpc SYMBOL,VALUES'...
=============================

Evaluate a sequence of statements assigning different values to SYMBOL.
The sequence of statements starts at the `.irpc' directive, and is
terminated by an `.endr' directive.  For each character in VALUE,
SYMBOL is set to the character, and the sequence of statements is
assembled.  If no VALUE is listed, the sequence of statements is
assembled once, with SYMBOL set to the null string.  To refer to SYMBOL
within the sequence of statements, use \SYMBOL.

   For example, assembling

             .irpc    param,123
             move    d\param,sp@-
             .endr

   is equivalent to assembling

             move    d1,sp@-
             move    d2,sp@-
             move    d3,sp@-

   For some caveats with the spelling of SYMBOL, see also the discussion
at *Note Macro::.


File: as.info,  Node: Lcomm,  Next: Lflags,  Prev: Irpc,  Up: Pseudo Ops

7.58 `.lcomm SYMBOL , LENGTH'
=============================

Reserve LENGTH (an absolute expression) bytes for a local common
denoted by SYMBOL.  The section and value of SYMBOL are those of the
new local common.  The addresses are allocated in the bss section, so
that at run-time the bytes start off zeroed.  SYMBOL is not declared
global (*note `.global': Global.), so is normally not visible to `ld'.

   Some targets permit a third argument to be used with `.lcomm'.  This
argument specifies the desired alignment of the symbol in the bss
section.

   The syntax for `.lcomm' differs slightly on the HPPA.  The syntax is
`SYMBOL .lcomm, LENGTH'; SYMBOL is optional.


File: as.info,  Node: Lflags,  Next: Line,  Prev: Lcomm,  Up: Pseudo Ops

7.59 `.lflags'
==============

`as' accepts this directive, for compatibility with other assemblers,
but ignores it.


File: as.info,  Node: Line,  Next: Linkonce,  Prev: Lflags,  Up: Pseudo Ops

7.60 `.line LINE-NUMBER'
========================

   Change the logical line number.  LINE-NUMBER must be an absolute
expression.  The next line has that logical line number.  Therefore any
other statements on the current line (after a statement separator
character) are reported as on logical line number LINE-NUMBER - 1.  One
day `as' will no longer support this directive: it is recognized only
for compatibility with existing assembler programs.

   Even though this is a directive associated with the `a.out' or
`b.out' object-code formats, `as' still recognizes it when producing
COFF output, and treats `.line' as though it were the COFF `.ln' _if_
it is found outside a `.def'/`.endef' pair.

   Inside a `.def', `.line' is, instead, one of the directives used by
compilers to generate auxiliary symbol information for debugging.


File: as.info,  Node: Linkonce,  Next: List,  Prev: Line,  Up: Pseudo Ops

7.61 `.linkonce [TYPE]'
=======================

Mark the current section so that the linker only includes a single copy
of it.  This may be used to include the same section in several
different object files, but ensure that the linker will only include it
once in the final output file.  The `.linkonce' pseudo-op must be used
for each instance of the section.  Duplicate sections are detected
based on the section name, so it should be unique.

   This directive is only supported by a few object file formats; as of
this writing, the only object file format which supports it is the
Portable Executable format used on Windows NT.

   The TYPE argument is optional.  If specified, it must be one of the
following strings.  For example:
     .linkonce same_size
   Not all types may be supported on all object file formats.

`discard'
     Silently discard duplicate sections.  This is the default.

`one_only'
     Warn if there are duplicate sections, but still keep only one copy.

`same_size'
     Warn if any of the duplicates have different sizes.

`same_contents'
     Warn if any of the duplicates do not have exactly the same
     contents.


File: as.info,  Node: Ln,  Next: LNS directives,  Prev: List,  Up: Pseudo Ops

7.62 `.ln LINE-NUMBER'
======================

`.ln' is a synonym for `.line'.


File: as.info,  Node: MRI,  Next: Noaltmacro,  Prev: Macro,  Up: Pseudo Ops

7.63 `.mri VAL'
===============

If VAL is non-zero, this tells `as' to enter MRI mode.  If VAL is zero,
this tells `as' to exit MRI mode.  This change affects code assembled
until the next `.mri' directive, or until the end of the file.  *Note
MRI mode: M.


File: as.info,  Node: List,  Next: Ln,  Prev: Linkonce,  Up: Pseudo Ops

7.64 `.list'
============

Control (in conjunction with the `.nolist' directive) whether or not
assembly listings are generated.  These two directives maintain an
internal counter (which is zero initially).   `.list' increments the
counter, and `.nolist' decrements it.  Assembly listings are generated
whenever the counter is greater than zero.

   By default, listings are disabled.  When you enable them (with the
`-a' command line option; *note Command-Line Options: Invoking.), the
initial value of the listing counter is one.


File: as.info,  Node: Long,  Next: Macro,  Prev: LNS directives,  Up: Pseudo Ops

7.65 `.long EXPRESSIONS'
========================

`.long' is the same as `.int', *note `.int': Int.


File: as.info,  Node: Macro,  Next: MRI,  Prev: Long,  Up: Pseudo Ops

7.66 `.macro'
=============

The commands `.macro' and `.endm' allow you to define macros that
generate assembly output.  For example, this definition specifies a
macro `sum' that puts a sequence of numbers into memory:

             .macro  sum from=0, to=5
             .long   \from
             .if     \to-\from
             sum     "(\from+1)",\to
             .endif
             .endm

With that definition, `SUM 0,5' is equivalent to this assembly input:

             .long   0
             .long   1
             .long   2
             .long   3
             .long   4
             .long   5

`.macro MACNAME'
`.macro MACNAME MACARGS ...'
     Begin the definition of a macro called MACNAME.  If your macro
     definition requires arguments, specify their names after the macro
     name, separated by commas or spaces.  You can qualify the macro
     argument to indicate whether all invocations must specify a
     non-blank value (through `:`req''), or whether it takes all of the
     remaining arguments (through `:`vararg'').  You can supply a
     default value for any macro argument by following the name with
     `=DEFLT'.  You cannot define two macros with the same MACNAME
     unless it has been subject to the `.purgem' directive (*Note
     Purgem::.) between the two definitions.  For example, these are
     all valid `.macro' statements:

    `.macro comm'
          Begin the definition of a macro called `comm', which takes no
          arguments.

    `.macro plus1 p, p1'
    `.macro plus1 p p1'
          Either statement begins the definition of a macro called
          `plus1', which takes two arguments; within the macro
          definition, write `\p' or `\p1' to evaluate the arguments.

    `.macro reserve_str p1=0 p2'
          Begin the definition of a macro called `reserve_str', with two
          arguments.  The first argument has a default value, but not
          the second.  After the definition is complete, you can call
          the macro either as `reserve_str A,B' (with `\p1' evaluating
          to A and `\p2' evaluating to B), or as `reserve_str ,B' (with
          `\p1' evaluating as the default, in this case `0', and `\p2'
          evaluating to B).

`.macro m p1:req, p2=0, p3:vararg'
     Begin the definition of a macro called `m', with at least three
     arguments.  The first argument must always have a value specified,
     but not the second, which instead has a default value. The third
     formal will get assigned all remaining arguments specified at
     invocation time.

     When you call a macro, you can specify the argument values either
     by position, or by keyword.  For example, `sum 9,17' is equivalent
     to `sum to=17, from=9'.

     Note that since each of the MACARGS can be an identifier exactly
     as any other one permitted by the target architecture, there may be
     occasional problems if the target hand-crafts special meanings to
     certain characters when they occur in a special position.  For
     example, if colon (`:') is generally permitted to be part of a
     symbol name, but the architecture specific code special-cases it
     when occuring as the final character of a symbol (to denote a
     label), then the macro parameter replacement code will have no way
     of knowing that and consider the whole construct (including the
     colon) an identifier, and check only this identifier for being the
     subject to parameter substitution.  In this example, besides the
     potential of just separating identifier and colon by white space,
     using alternate macro syntax (*Note Altmacro::.) and ampersand
     (`&') as the character to separate literal text from macro
     parameters (or macro parameters from one another) would provide a
     way to achieve the same effect:

          	.altmacro
          	.macro label l
          l&:
          	.endm

     This applies identically to the identifiers used in `.irp' (*Note
     Irp::.)  and `.irpc' (*Note Irpc::.).

`.endm'
     Mark the end of a macro definition.

`.exitm'
     Exit early from the current macro definition.

`\@'
     `as' maintains a counter of how many macros it has executed in
     this pseudo-variable; you can copy that number to your output with
     `\@', but _only within a macro definition_.

`LOCAL NAME [ , ... ]'
     _Warning: `LOCAL' is only available if you select "alternate macro
     syntax" with `--alternate' or `.altmacro'._ *Note `.altmacro':
     Altmacro.


File: as.info,  Node: Altmacro,  Next: Ascii,  Prev: Align,  Up: Pseudo Ops

7.67 `.altmacro'
================

Enable alternate macro mode, enabling:

`LOCAL NAME [ , ... ]'
     One additional directive, `LOCAL', is available.  It is used to
     generate a string replacement for each of the NAME arguments, and
     replace any instances of NAME in each macro expansion.  The
     replacement string is unique in the assembly, and different for
     each separate macro expansion.  `LOCAL' allows you to write macros
     that define symbols, without fear of conflict between separate
     macro expansions.

`String delimiters'
     You can write strings delimited in these other ways besides
     `"STRING"':

    `'STRING''
          You can delimit strings with single-quote charaters.

    `<STRING>'
          You can delimit strings with matching angle brackets.

`single-character string escape'
     To include any single character literally in a string (even if the
     character would otherwise have some special meaning), you can
     prefix the character with `!' (an exclamation mark).  For example,
     you can write `<4.3 !> 5.4!!>' to get the literal text `4.3 >
     5.4!'.

`Expression results as strings'
     You can write `%EXPR' to evaluate the expression EXPR and use the
     result as a string.


File: as.info,  Node: Noaltmacro,  Next: Nolist,  Prev: MRI,  Up: Pseudo Ops

7.68 `.noaltmacro'
==================

Disable alternate macro mode.  *Note Altmacro::


File: as.info,  Node: Nolist,  Next: Octa,  Prev: Noaltmacro,  Up: Pseudo Ops

7.69 `.nolist'
==============

Control (in conjunction with the `.list' directive) whether or not
assembly listings are generated.  These two directives maintain an
internal counter (which is zero initially).   `.list' increments the
counter, and `.nolist' decrements it.  Assembly listings are generated
whenever the counter is greater than zero.


File: as.info,  Node: Octa,  Next: Org,  Prev: Nolist,  Up: Pseudo Ops

7.70 `.octa BIGNUMS'
====================

This directive expects zero or more bignums, separated by commas.  For
each bignum, it emits a 16-byte integer.

   The term "octa" comes from contexts in which a "word" is two bytes;
hence _octa_-word for 16 bytes.


File: as.info,  Node: Org,  Next: P2align,  Prev: Octa,  Up: Pseudo Ops

7.71 `.org NEW-LC , FILL'
=========================

Advance the location counter of the current section to NEW-LC.  NEW-LC
is either an absolute expression or an expression with the same section
as the current subsection.  That is, you can't use `.org' to cross
sections: if NEW-LC has the wrong section, the `.org' directive is
ignored.  To be compatible with former assemblers, if the section of
NEW-LC is absolute, `as' issues a warning, then pretends the section of
NEW-LC is the same as the current subsection.

   `.org' may only increase the location counter, or leave it
unchanged; you cannot use `.org' to move the location counter backwards.

   Because `as' tries to assemble programs in one pass, NEW-LC may not
be undefined.  If you really detest this restriction we eagerly await a
chance to share your improved assembler.

   Beware that the origin is relative to the start of the section, not
to the start of the subsection.  This is compatible with other people's
assemblers.

   When the location counter (of the current subsection) is advanced,
the intervening bytes are filled with FILL which should be an absolute
expression.  If the comma and FILL are omitted, FILL defaults to zero.


File: as.info,  Node: P2align,  Next: PopSection,  Prev: Org,  Up: Pseudo Ops

7.72 `.p2align[wl] ABS-EXPR, ABS-EXPR, ABS-EXPR'
================================================

Pad the location counter (in the current subsection) to a particular
storage boundary.  The first expression (which must be absolute) is the
number of low-order zero bits the location counter must have after
advancement.  For example `.p2align 3' advances the location counter
until it a multiple of 8.  If the location counter is already a
multiple of 8, no change is needed.

   The second expression (also absolute) gives the fill value to be
stored in the padding bytes.  It (and the comma) may be omitted.  If it
is omitted, the padding bytes are normally zero.  However, on some
systems, if the section is marked as containing code and the fill value
is omitted, the space is filled with no-op instructions.

   The third expression is also absolute, and is also optional.  If it
is present, it is the maximum number of bytes that should be skipped by
this alignment directive.  If doing the alignment would require
skipping more bytes than the specified maximum, then the alignment is
not done at all.  You can omit the fill value (the second argument)
entirely by simply using two commas after the required alignment; this
can be useful if you want the alignment to be filled with no-op
instructions when appropriate.

   The `.p2alignw' and `.p2alignl' directives are variants of the
`.p2align' directive.  The `.p2alignw' directive treats the fill
pattern as a two byte word value.  The `.p2alignl' directives treats the
fill pattern as a four byte longword value.  For example, `.p2alignw
2,0x368d' will align to a multiple of 4.  If it skips two bytes, they
will be filled in with the value 0x368d (the exact placement of the
bytes depends upon the endianness of the processor).  If it skips 1 or
3 bytes, the fill value is undefined.


File: as.info,  Node: Previous,  Next: Print,  Prev: PopSection,  Up: Pseudo Ops

7.73 `.previous'
================

This is one of the ELF section stack manipulation directives.  The
others are `.section' (*note Section::), `.subsection' (*note
SubSection::), `.pushsection' (*note PushSection::), and `.popsection'
(*note PopSection::).

   This directive swaps the current section (and subsection) with most
recently referenced section (and subsection) prior to this one.
Multiple `.previous' directives in a row will flip between two sections
(and their subsections).

   In terms of the section stack, this directive swaps the current
section with the top section on the section stack.


File: as.info,  Node: PopSection,  Next: Previous,  Prev: P2align,  Up: Pseudo Ops

7.74 `.popsection'
==================

This is one of the ELF section stack manipulation directives.  The
others are `.section' (*note Section::), `.subsection' (*note
SubSection::), `.pushsection' (*note PushSection::), and `.previous'
(*note Previous::).

   This directive replaces the current section (and subsection) with
the top section (and subsection) on the section stack.  This section is
popped off the stack.


File: as.info,  Node: Print,  Next: Protected,  Prev: Previous,  Up: Pseudo Ops

7.75 `.print STRING'
====================

`as' will print STRING on the standard output during assembly.  You
must put STRING in double quotes.


File: as.info,  Node: Protected,  Next: Psize,  Prev: Print,  Up: Pseudo Ops

7.76 `.protected NAMES'
=======================

This is one of the ELF visibility directives.  The other two are
`.hidden' (*note Hidden::) and `.internal' (*note Internal::).

   This directive overrides the named symbols default visibility (which
is set by their binding: local, global or weak).  The directive sets
the visibility to `protected' which means that any references to the
symbols from within the components that defines them must be resolved
to the definition in that component, even if a definition in another
component would normally preempt this.


File: as.info,  Node: Psize,  Next: Purgem,  Prev: Protected,  Up: Pseudo Ops

7.77 `.psize LINES , COLUMNS'
=============================

Use this directive to declare the number of lines--and, optionally, the
number of columns--to use for each page, when generating listings.

   If you do not use `.psize', listings use a default line-count of 60.
You may omit the comma and COLUMNS specification; the default width is
200 columns.

   `as' generates formfeeds whenever the specified number of lines is
exceeded (or whenever you explicitly request one, using `.eject').

   If you specify LINES as `0', no formfeeds are generated save those
explicitly specified with `.eject'.


File: as.info,  Node: Purgem,  Next: PushSection,  Prev: Psize,  Up: Pseudo Ops

7.78 `.purgem NAME'
===================

Undefine the macro NAME, so that later uses of the string will not be
expanded.  *Note Macro::.


File: as.info,  Node: PushSection,  Next: Quad,  Prev: Purgem,  Up: Pseudo Ops

7.79 `.pushsection NAME , SUBSECTION'
=====================================

This is one of the ELF section stack manipulation directives.  The
others are `.section' (*note Section::), `.subsection' (*note
SubSection::), `.popsection' (*note PopSection::), and `.previous'
(*note Previous::).

   This directive pushes the current section (and subsection) onto the
top of the section stack, and then replaces the current section and
subsection with `name' and `subsection'.


File: as.info,  Node: Quad,  Next: Rept,  Prev: PushSection,  Up: Pseudo Ops

7.80 `.quad BIGNUMS'
====================

`.quad' expects zero or more bignums, separated by commas.  For each
bignum, it emits an 8-byte integer.  If the bignum won't fit in 8
bytes, it prints a warning message; and just takes the lowest order 8
bytes of the bignum.  

   The term "quad" comes from contexts in which a "word" is two bytes;
hence _quad_-word for 8 bytes.


File: as.info,  Node: Rept,  Next: Sbttl,  Prev: Quad,  Up: Pseudo Ops

7.81 `.rept COUNT'
==================

Repeat the sequence of lines between the `.rept' directive and the next
`.endr' directive COUNT times.

   For example, assembling

             .rept   3
             .long   0
             .endr

   is equivalent to assembling

             .long   0
             .long   0
             .long   0


File: as.info,  Node: Sbttl,  Next: Scl,  Prev: Rept,  Up: Pseudo Ops

7.82 `.sbttl "SUBHEADING"'
==========================

Use SUBHEADING as the title (third line, immediately after the title
line) when generating assembly listings.

   This directive affects subsequent pages, as well as the current page
if it appears within ten lines of the top of a page.


File: as.info,  Node: Scl,  Next: Section,  Prev: Sbttl,  Up: Pseudo Ops

7.83 `.scl CLASS'
=================

Set the storage-class value for a symbol.  This directive may only be
used inside a `.def'/`.endef' pair.  Storage class may flag whether a
symbol is static or external, or it may record further symbolic
debugging information.


File: as.info,  Node: Section,  Next: Set,  Prev: Scl,  Up: Pseudo Ops

7.84 `.section NAME'
====================

Use the `.section' directive to assemble the following code into a
section named NAME.

   This directive is only supported for targets that actually support
arbitrarily named sections; on `a.out' targets, for example, it is not
accepted, even with a standard `a.out' section name.

COFF Version
------------

   For COFF targets, the `.section' directive is used in one of the
following ways:

     .section NAME[, "FLAGS"]
     .section NAME[, SUBSEGMENT]

   If the optional argument is quoted, it is taken as flags to use for
the section.  Each flag is a single character.  The following flags are
recognized:
`b'
     bss section (uninitialized data)

`n'
     section is not loaded

`w'
     writable section

`d'
     data section

`r'
     read-only section

`x'
     executable section

`s'
     shared section (meaningful for PE targets)

`a'
     ignored.  (For compatibility with the ELF version)

   If no flags are specified, the default flags depend upon the section
name.  If the section name is not recognized, the default will be for
the section to be loaded and writable.  Note the `n' and `w' flags
remove attributes from the section, rather than adding them, so if they
are used on their own it will be as if no flags had been specified at
all.

   If the optional argument to the `.section' directive is not quoted,
it is taken as a subsegment number (*note Sub-Sections::).

ELF Version
-----------

   This is one of the ELF section stack manipulation directives.  The
others are `.subsection' (*note SubSection::), `.pushsection' (*note
PushSection::), `.popsection' (*note PopSection::), and `.previous'
(*note Previous::).

   For ELF targets, the `.section' directive is used like this:

     .section NAME [, "FLAGS"[, @TYPE[,FLAG_SPECIFIC_ARGUMENTS]]]

   The optional FLAGS argument is a quoted string which may contain any
combination of the following characters:
`a'
     section is allocatable

`w'
     section is writable

`x'
     section is executable

`M'
     section is mergeable

`S'
     section contains zero terminated strings

`G'
     section is a member of a section group

`T'
     section is used for thread-local-storage

   The optional TYPE argument may contain one of the following
constants:
`@progbits'
     section contains data

`@nobits'
     section does not contain data (i.e., section only occupies space)

`@note'
     section contains data which is used by things other than the
     program

`@init_array'
     section contains an array of pointers to init functions

`@fini_array'
     section contains an array of pointers to finish functions

`@preinit_array'
     section contains an array of pointers to pre-init functions

   Many targets only support the first three section types.

   Note on targets where the `@' character is the start of a comment (eg
ARM) then another character is used instead.  For example the ARM port
uses the `%' character.

   If FLAGS contains the `M' symbol then the TYPE argument must be
specified as well as an extra argument - ENTSIZE - like this:

     .section NAME , "FLAGS"M, @TYPE, ENTSIZE

   Sections with the `M' flag but not `S' flag must contain fixed size
constants, each ENTSIZE octets long. Sections with both `M' and `S'
must contain zero terminated strings where each character is ENTSIZE
bytes long. The linker may remove duplicates within sections with the
same name, same entity size and same flags.  ENTSIZE must be an
absolute expression.

   If FLAGS contains the `G' symbol then the TYPE argument must be
present along with an additional field like this:

     .section NAME , "FLAGS"G, @TYPE, GROUPNAME[, LINKAGE]

   The GROUPNAME field specifies the name of the section group to which
this particular section belongs.  The optional linkage field can
contain:
`comdat'
     indicates that only one copy of this section should be retained

`.gnu.linkonce'
     an alias for comdat

   Note - if both the M and G flags are present then the fields for the
Merge flag should come first, like this:

     .section NAME , "FLAGS"MG, @TYPE, ENTSIZE, GROUPNAME[, LINKAGE]

   If no flags are specified, the default flags depend upon the section
name.  If the section name is not recognized, the default will be for
the section to have none of the above flags: it will not be allocated
in memory, nor writable, nor executable.  The section will contain data.

   For ELF targets, the assembler supports another type of `.section'
directive for compatibility with the Solaris assembler:

     .section "NAME"[, FLAGS...]

   Note that the section name is quoted.  There may be a sequence of
comma separated flags:
`#alloc'
     section is allocatable

`#write'
     section is writable

`#execinstr'
     section is executable

`#tls'
     section is used for thread local storage

   This directive replaces the current section and subsection.  See the
contents of the gas testsuite directory `gas/testsuite/gas/elf' for
some examples of how this directive and the other section stack
directives work.


File: as.info,  Node: Set,  Next: Short,  Prev: Section,  Up: Pseudo Ops

7.85 `.set SYMBOL, EXPRESSION'
==============================

Set the value of SYMBOL to EXPRESSION.  This changes SYMBOL's value and
type to conform to EXPRESSION.  If SYMBOL was flagged as external, it
remains flagged (*note Symbol Attributes::).

   You may `.set' a symbol many times in the same assembly.

   If you `.set' a global symbol, the value stored in the object file
is the last value stored into it.

   The syntax for `set' on the HPPA is `SYMBOL .set EXPRESSION'.

   On Z80 `set' is a real instruction, use `SYMBOL defl EXPRESSION'
instead.


File: as.info,  Node: Short,  Next: Single,  Prev: Set,  Up: Pseudo Ops

7.86 `.short EXPRESSIONS'
=========================

`.short' is normally the same as `.word'.  *Note `.word': Word.

   In some configurations, however, `.short' and `.word' generate
numbers of different lengths; *note Machine Dependencies::.


File: as.info,  Node: Single,  Next: Size,  Prev: Short,  Up: Pseudo Ops

7.87 `.single FLONUMS'
======================

This directive assembles zero or more flonums, separated by commas.  It
has the same effect as `.float'.  The exact kind of floating point
numbers emitted depends on how `as' is configured.  *Note Machine
Dependencies::.


File: as.info,  Node: Size,  Next: Skip,  Prev: Single,  Up: Pseudo Ops

7.88 `.size'
============

This directive is used to set the size associated with a symbol.

COFF Version
------------

   For COFF targets, the `.size' directive is only permitted inside
`.def'/`.endef' pairs.  It is used like this:

     .size EXPRESSION

ELF Version
-----------

   For ELF targets, the `.size' directive is used like this:

     .size NAME , EXPRESSION

   This directive sets the size associated with a symbol NAME.  The
size in bytes is computed from EXPRESSION which can make use of label
arithmetic.  This directive is typically used to set the size of
function symbols.


File: as.info,  Node: Sleb128,  Next: Space,  Prev: Skip,  Up: Pseudo Ops

7.89 `.sleb128 EXPRESSIONS'
===========================

SLEB128 stands for "signed little endian base 128."  This is a compact,
variable length representation of numbers used by the DWARF symbolic
debugging format.  *Note `.uleb128': Uleb128.


File: as.info,  Node: Skip,  Next: Sleb128,  Prev: Size,  Up: Pseudo Ops

7.90 `.skip SIZE , FILL'
========================

This directive emits SIZE bytes, each of value FILL.  Both SIZE and
FILL are absolute expressions.  If the comma and FILL are omitted, FILL
is assumed to be zero.  This is the same as `.space'.


File: as.info,  Node: Space,  Next: Stab,  Prev: Sleb128,  Up: Pseudo Ops

7.91 `.space SIZE , FILL'
=========================

This directive emits SIZE bytes, each of value FILL.  Both SIZE and
FILL are absolute expressions.  If the comma and FILL are omitted, FILL
is assumed to be zero.  This is the same as `.skip'.

     _Warning:_ `.space' has a completely different meaning for HPPA
     targets; use `.block' as a substitute.  See `HP9000 Series 800
     Assembly Language Reference Manual' (HP 92432-90001) for the
     meaning of the `.space' directive.  *Note HPPA Assembler
     Directives: HPPA Directives, for a summary.


File: as.info,  Node: Stab,  Next: String,  Prev: Space,  Up: Pseudo Ops

7.92 `.stabd, .stabn, .stabs'
=============================

There are three directives that begin `.stab'.  All emit symbols (*note
Symbols::), for use by symbolic debuggers.  The symbols are not entered
in the `as' hash table: they cannot be referenced elsewhere in the
source file.  Up to five fields are required:

STRING
     This is the symbol's name.  It may contain any character except
     `\000', so is more general than ordinary symbol names.  Some
     debuggers used to code arbitrarily complex structures into symbol
     names using this field.

TYPE
     An absolute expression.  The symbol's type is set to the low 8
     bits of this expression.  Any bit pattern is permitted, but `ld'
     and debuggers choke on silly bit patterns.

OTHER
     An absolute expression.  The symbol's "other" attribute is set to
     the low 8 bits of this expression.

DESC
     An absolute expression.  The symbol's descriptor is set to the low
     16 bits of this expression.

VALUE
     An absolute expression which becomes the symbol's value.

   If a warning is detected while reading a `.stabd', `.stabn', or
`.stabs' statement, the symbol has probably already been created; you
get a half-formed symbol in your object file.  This is compatible with
earlier assemblers!

`.stabd TYPE , OTHER , DESC'
     The "name" of the symbol generated is not even an empty string.
     It is a null pointer, for compatibility.  Older assemblers used a
     null pointer so they didn't waste space in object files with empty
     strings.

     The symbol's value is set to the location counter, relocatably.
     When your program is linked, the value of this symbol is the
     address of the location counter when the `.stabd' was assembled.

`.stabn TYPE , OTHER , DESC , VALUE'
     The name of the symbol is set to the empty string `""'.

`.stabs STRING ,  TYPE , OTHER , DESC , VALUE'
     All five fields are specified.


File: as.info,  Node: String,  Next: Struct,  Prev: Stab,  Up: Pseudo Ops

7.93 `.string' "STR"
====================

Copy the characters in STR to the object file.  You may specify more
than one string to copy, separated by commas.  Unless otherwise
specified for a particular machine, the assembler marks the end of each
string with a 0 byte.  You can use any of the escape sequences
described in *Note Strings: Strings.


File: as.info,  Node: Struct,  Next: SubSection,  Prev: String,  Up: Pseudo Ops

7.94 `.struct EXPRESSION'
=========================

Switch to the absolute section, and set the section offset to
EXPRESSION, which must be an absolute expression.  You might use this
as follows:
             .struct 0
     field1:
             .struct field1 + 4
     field2:
             .struct field2 + 4
     field3:
   This would define the symbol `field1' to have the value 0, the symbol
`field2' to have the value 4, and the symbol `field3' to have the value
8.  Assembly would be left in the absolute section, and you would need
to use a `.section' directive of some sort to change to some other
section before further assembly.


File: as.info,  Node: SubSection,  Next: Symver,  Prev: Struct,  Up: Pseudo Ops

7.95 `.subsection NAME'
=======================

This is one of the ELF section stack manipulation directives.  The
others are `.section' (*note Section::), `.pushsection' (*note
PushSection::), `.popsection' (*note PopSection::), and `.previous'
(*note Previous::).

   This directive replaces the current subsection with `name'.  The
current section is not changed.  The replaced subsection is put onto
the section stack in place of the then current top of stack subsection.


File: as.info,  Node: Symver,  Next: Tag,  Prev: SubSection,  Up: Pseudo Ops

7.96 `.symver'
==============

Use the `.symver' directive to bind symbols to specific version nodes
within a source file.  This is only supported on ELF platforms, and is
typically used when assembling files to be linked into a shared library.
There are cases where it may make sense to use this in objects to be
bound into an application itself so as to override a versioned symbol
from a shared library.

   For ELF targets, the `.symver' directive can be used like this:
     .symver NAME, NAME2@NODENAME
   If the symbol NAME is defined within the file being assembled, the
`.symver' directive effectively creates a symbol alias with the name
NAME2@NODENAME, and in fact the main reason that we just don't try and
create a regular alias is that the @ character isn't permitted in
symbol names.  The NAME2 part of the name is the actual name of the
symbol by which it will be externally referenced.  The name NAME itself
is merely a name of convenience that is used so that it is possible to
have definitions for multiple versions of a function within a single
source file, and so that the compiler can unambiguously know which
version of a function is being mentioned.  The NODENAME portion of the
alias should be the name of a node specified in the version script
supplied to the linker when building a shared library.  If you are
attempting to override a versioned symbol from a shared library, then
NODENAME should correspond to the nodename of the symbol you are trying
to override.

   If the symbol NAME is not defined within the file being assembled,
all references to NAME will be changed to NAME2@NODENAME.  If no
reference to NAME is made, NAME2@NODENAME will be removed from the
symbol table.

   Another usage of the `.symver' directive is:
     .symver NAME, NAME2@@NODENAME
   In this case, the symbol NAME must exist and be defined within the
file being assembled. It is similar to NAME2@NODENAME. The difference
is NAME2@@NODENAME will also be used to resolve references to NAME2 by
the linker.

   The third usage of the `.symver' directive is:
     .symver NAME, NAME2@@@NODENAME
   When NAME is not defined within the file being assembled, it is
treated as NAME2@NODENAME. When NAME is defined within the file being
assembled, the symbol name, NAME, will be changed to NAME2@@NODENAME.


File: as.info,  Node: Tag,  Next: Text,  Prev: Symver,  Up: Pseudo Ops

7.97 `.tag STRUCTNAME'
======================

This directive is generated by compilers to include auxiliary debugging
information in the symbol table.  It is only permitted inside
`.def'/`.endef' pairs.  Tags are used to link structure definitions in
the symbol table with instances of those structures.


File: as.info,  Node: Text,  Next: Title,  Prev: Tag,  Up: Pseudo Ops

7.98 `.text SUBSECTION'
=======================

Tells `as' to assemble the following statements onto the end of the
text subsection numbered SUBSECTION, which is an absolute expression.
If SUBSECTION is omitted, subsection number zero is used.


File: as.info,  Node: Title,  Next: Type,  Prev: Text,  Up: Pseudo Ops

7.99 `.title "HEADING"'
=======================

Use HEADING as the title (second line, immediately after the source
file name and pagenumber) when generating assembly listings.

   This directive affects subsequent pages, as well as the current page
if it appears within ten lines of the top of a page.


File: as.info,  Node: Type,  Next: Uleb128,  Prev: Title,  Up: Pseudo Ops

7.100 `.type'
=============

This directive is used to set the type of a symbol.

COFF Version
------------

   For COFF targets, this directive is permitted only within
`.def'/`.endef' pairs.  It is used like this:

     .type INT

   This records the integer INT as the type attribute of a symbol table
entry.

ELF Version
-----------

   For ELF targets, the `.type' directive is used like this:

     .type NAME , TYPE DESCRIPTION

   This sets the type of symbol NAME to be either a function symbol or
an object symbol.  There are five different syntaxes supported for the
TYPE DESCRIPTION field, in order to provide compatibility with various
other assemblers.  The syntaxes supported are:

       .type <name>,#function
       .type <name>,#object

       .type <name>,@function
       .type <name>,@object

       .type <name>,%function
       .type <name>,%object

       .type <name>,"function"
       .type <name>,"object"

       .type <name> STT_FUNCTION
       .type <name> STT_OBJECT


File: as.info,  Node: Uleb128,  Next: Val,  Prev: Type,  Up: Pseudo Ops

7.101 `.uleb128 EXPRESSIONS'
============================

ULEB128 stands for "unsigned little endian base 128."  This is a
compact, variable length representation of numbers used by the DWARF
symbolic debugging format.  *Note `.sleb128': Sleb128.


File: as.info,  Node: Val,  Next: Version,  Prev: Uleb128,  Up: Pseudo Ops

7.102 `.val ADDR'
=================

This directive, permitted only within `.def'/`.endef' pairs, records
the address ADDR as the value attribute of a symbol table entry.


File: as.info,  Node: Version,  Next: VTableEntry,  Prev: Val,  Up: Pseudo Ops

7.103 `.version "STRING"'
=========================

This directive creates a `.note' section and places into it an ELF
formatted note of type NT_VERSION.  The note's name is set to `string'.


File: as.info,  Node: VTableEntry,  Next: VTableInherit,  Prev: Version,  Up: Pseudo Ops

7.104 `.vtable_entry TABLE, OFFSET'
===================================

This directive finds or creates a symbol `table' and creates a
`VTABLE_ENTRY' relocation for it with an addend of `offset'.


File: as.info,  Node: VTableInherit,  Next: Warning,  Prev: VTableEntry,  Up: Pseudo Ops

7.105 `.vtable_inherit CHILD, PARENT'
=====================================

This directive finds the symbol `child' and finds or creates the symbol
`parent' and then creates a `VTABLE_INHERIT' relocation for the parent
whose addend is the value of the child symbol.  As a special case the
parent name of `0' is treated as refering the `*ABS*' section.


File: as.info,  Node: Warning,  Next: Weak,  Prev: VTableInherit,  Up: Pseudo Ops

7.106 `.warning "STRING"'
=========================

Similar to the directive `.error' (*note `.error "STRING"': Error.),
but just emits a warning.


File: as.info,  Node: Weak,  Next: Weakref,  Prev: Warning,  Up: Pseudo Ops

7.107 `.weak NAMES'
===================

This directive sets the weak attribute on the comma separated list of
symbol `names'.  If the symbols do not already exist, they will be
created.

   On COFF targets other than PE, weak symbols are a GNU extension.
This directive sets the weak attribute on the comma separated list of
symbol `names'.  If the symbols do not already exist, they will be
created.

   On the PE target, weak symbols are supported natively as weak
aliases.  When a weak symbol is created that is not an alias, GAS
creates an alternate symbol to hold the default value.


File: as.info,  Node: Weakref,  Next: Word,  Prev: Weak,  Up: Pseudo Ops

7.108 `.weakref ALIAS, TARGET'
==============================

This directive creates an alias to the target symbol that enables the
symbol to be referenced with weak-symbol semantics, but without
actually making it weak.  If direct references or definitions of the
symbol are present, then the symbol will not be weak, but if all
references to it are through weak references, the symbol will be marked
as weak in the symbol table.

   The effect is equivalent to moving all references to the alias to a
separate assembly source file, renaming the alias to the symbol in it,
declaring the symbol as weak there, and running a reloadable link to
merge the object files resulting from the assembly of the new source
file and the old source file that had the references to the alias
removed.

   The alias itself never makes to the symbol table, and is entirely
handled within the assembler.


File: as.info,  Node: Word,  Next: Deprecated,  Prev: Weakref,  Up: Pseudo Ops

7.109 `.word EXPRESSIONS'
=========================

This directive expects zero or more EXPRESSIONS, of any section,
separated by commas.

   The size of the number emitted, and its byte order, depend on what
target computer the assembly is for.

     _Warning: Special Treatment to support Compilers_

   Machines with a 32-bit address space, but that do less than 32-bit
addressing, require the following special treatment.  If the machine of
interest to you does 32-bit addressing (or doesn't require it; *note
Machine Dependencies::), you can ignore this issue.

   In order to assemble compiler output into something that works, `as'
occasionally does strange things to `.word' directives.  Directives of
the form `.word sym1-sym2' are often emitted by compilers as part of
jump tables.  Therefore, when `as' assembles a directive of the form
`.word sym1-sym2', and the difference between `sym1' and `sym2' does
not fit in 16 bits, `as' creates a "secondary jump table", immediately
before the next label.  This secondary jump table is preceded by a
short-jump to the first byte after the secondary table.  This
short-jump prevents the flow of control from accidentally falling into
the new table.  Inside the table is a long-jump to `sym2'.  The
original `.word' contains `sym1' minus the address of the long-jump to
`sym2'.

   If there were several occurrences of `.word sym1-sym2' before the
secondary jump table, all of them are adjusted.  If there was a `.word
sym3-sym4', that also did not fit in sixteen bits, a long-jump to
`sym4' is included in the secondary jump table, and the `.word'
directives are adjusted to contain `sym3' minus the address of the
long-jump to `sym4'; and so on, for as many entries in the original
jump table as necessary.


File: as.info,  Node: Deprecated,  Prev: Word,  Up: Pseudo Ops

7.110 Deprecated Directives
===========================

One day these directives won't work.  They are included for
compatibility with older assemblers.
.abort

.line


File: as.info,  Node: Machine Dependencies,  Next: Reporting Bugs,  Prev: Pseudo Ops,  Up: Top

8 Machine Dependent Features
****************************

The machine instruction sets are (almost by definition) different on
each machine where `as' runs.  Floating point representations vary as
well, and `as' often supports a few additional directives or
command-line options for compatibility with other assemblers on a
particular platform.  Finally, some versions of `as' support special
pseudo-instructions for branch optimization.

   This chapter discusses most of these differences, though it does not
include details on any machine's instruction set.  For details on that
subject, see the hardware manufacturer's manual.

* Menu:


* Alpha-Dependent::		Alpha Dependent Features

* ARC-Dependent::               ARC Dependent Features

* ARM-Dependent::               ARM Dependent Features

* BFIN-Dependent::		BFIN Dependent Features

* CRIS-Dependent::              CRIS Dependent Features

* D10V-Dependent::              D10V Dependent Features

* D30V-Dependent::              D30V Dependent Features

* H8/300-Dependent::            Renesas H8/300 Dependent Features

* HPPA-Dependent::              HPPA Dependent Features

* ESA/390-Dependent::           IBM ESA/390 Dependent Features

* i386-Dependent::              Intel 80386 and AMD x86-64 Dependent Features

* i860-Dependent::              Intel 80860 Dependent Features

* i960-Dependent::              Intel 80960 Dependent Features

* IA-64-Dependent::             Intel IA-64 Dependent Features

* IP2K-Dependent::              IP2K Dependent Features

* M32C-Dependent::              M32C Dependent Features

* M32R-Dependent::              M32R Dependent Features

* M68K-Dependent::              M680x0 Dependent Features

* M68HC11-Dependent::           M68HC11 and 68HC12 Dependent Features

* MIPS-Dependent::              MIPS Dependent Features

* MMIX-Dependent::              MMIX Dependent Features

* MSP430-Dependent::		MSP430 Dependent Features

* SH-Dependent::                Renesas / SuperH SH Dependent Features
* SH64-Dependent::              SuperH SH64 Dependent Features

* PDP-11-Dependent::            PDP-11 Dependent Features

* PJ-Dependent::                picoJava Dependent Features

* PPC-Dependent::               PowerPC Dependent Features

* Sparc-Dependent::             SPARC Dependent Features

* TIC54X-Dependent::            TI TMS320C54x Dependent Features

* V850-Dependent::              V850 Dependent Features

* Xtensa-Dependent::            Xtensa Dependent Features

* Z80-Dependent::               Z80 Dependent Features

* Z8000-Dependent::             Z8000 Dependent Features

* Vax-Dependent::               VAX Dependent Features


File: as.info,  Node: Alpha-Dependent,  Next: ARC-Dependent,  Up: Machine Dependencies

8.1 Alpha Dependent Features
============================

* Menu:

* Alpha Notes::                Notes
* Alpha Options::              Options
* Alpha Syntax::               Syntax
* Alpha Floating Point::       Floating Point
* Alpha Directives::           Alpha Machine Directives
* Alpha Opcodes::              Opcodes


File: as.info,  Node: Alpha Notes,  Next: Alpha Options,  Up: Alpha-Dependent

8.1.1 Notes
-----------

The documentation here is primarily for the ELF object format.  `as'
also supports the ECOFF and EVAX formats, but features specific to
these formats are not yet documented.


File: as.info,  Node: Alpha Options,  Next: Alpha Syntax,  Prev: Alpha Notes,  Up: Alpha-Dependent

8.1.2 Options
-------------

`-mCPU'
     This option specifies the target processor.  If an attempt is made
     to assemble an instruction which will not execute on the target
     processor, the assembler may either expand the instruction as a
     macro or issue an error message.  This option is equivalent to the
     `.arch' directive.

     The following processor names are recognized: `21064', `21064a',
     `21066', `21068', `21164', `21164a', `21164pc', `21264', `21264a',
     `21264b', `ev4', `ev5', `lca45', `ev5', `ev56', `pca56', `ev6',
     `ev67', `ev68'.  The special name `all' may be used to allow the
     assembler to accept instructions valid for any Alpha processor.

     In order to support existing practice in OSF/1 with respect to
     `.arch', and existing practice within `MILO' (the Linux ARC
     bootloader), the numbered processor names (e.g. 21064) enable the
     processor-specific PALcode instructions, while the
     "electro-vlasic" names (e.g. `ev4') do not.

`-mdebug'
`-no-mdebug'
     Enables or disables the generation of `.mdebug' encapsulation for
     stabs directives and procedure descriptors.  The default is to
     automatically enable `.mdebug' when the first stabs directive is
     seen.

`-relax'
     This option forces all relocations to be put into the object file,
     instead of saving space and resolving some relocations at assembly
     time.  Note that this option does not propagate all symbol
     arithmetic into the object file, because not all symbol arithmetic
     can be represented.  However, the option can still be useful in
     specific applications.

`-g'
     This option is used when the compiler generates debug information.
     When `gcc' is using `mips-tfile' to generate debug information
     for ECOFF, local labels must be passed through to the object file.
     Otherwise this option has no effect.

`-GSIZE'
     A local common symbol larger than SIZE is placed in `.bss', while
     smaller symbols are placed in `.sbss'.

`-F'
`-32addr'
     These options are ignored for backward compatibility.


File: as.info,  Node: Alpha Syntax,  Next: Alpha Floating Point,  Prev: Alpha Options,  Up: Alpha-Dependent

8.1.3 Syntax
------------

The assembler syntax closely follow the Alpha Reference Manual;
assembler directives and general syntax closely follow the OSF/1 and
OpenVMS syntax, with a few differences for ELF.

* Menu:

* Alpha-Chars::                Special Characters
* Alpha-Regs::                 Register Names
* Alpha-Relocs::               Relocations


File: as.info,  Node: Alpha-Chars,  Next: Alpha-Regs,  Up: Alpha Syntax

8.1.3.1 Special Characters
..........................

`#' is the line comment character.

   `;' can be used instead of a newline to separate statements.


File: as.info,  Node: Alpha-Regs,  Next: Alpha-Relocs,  Prev: Alpha-Chars,  Up: Alpha Syntax

8.1.3.2 Register Names
......................

The 32 integer registers are referred to as `$N' or `$rN'.  In
addition, registers 15, 28, 29, and 30 may be referred to by the
symbols `$fp', `$at', `$gp', and `$sp' respectively.

   The 32 floating-point registers are referred to as `$fN'.


File: as.info,  Node: Alpha-Relocs,  Prev: Alpha-Regs,  Up: Alpha Syntax

8.1.3.3 Relocations
...................

Some of these relocations are available for ECOFF, but mostly only for
ELF.  They are modeled after the relocation format introduced in
Digital Unix 4.0, but there are additions.

   The format is `!TAG' or `!TAG!NUMBER' where TAG is the name of the
relocation.  In some cases NUMBER is used to relate specific
instructions.

   The relocation is placed at the end of the instruction like so:

     ldah  $0,a($29)    !gprelhigh
     lda   $0,a($0)     !gprellow
     ldq   $1,b($29)    !literal!100
     ldl   $2,0($1)     !lituse_base!100

`!literal'
`!literal!N'
     Used with an `ldq' instruction to load the address of a symbol
     from the GOT.

     A sequence number N is optional, and if present is used to pair
     `lituse' relocations with this `literal' relocation.  The `lituse'
     relocations are used by the linker to optimize the code based on
     the final location of the symbol.

     Note that these optimizations are dependent on the data flow of the
     program.  Therefore, if _any_ `lituse' is paired with a `literal'
     relocation, then _all_ uses of the register set by the `literal'
     instruction must also be marked with `lituse' relocations.  This
     is because the original `literal' instruction may be deleted or
     transformed into another instruction.

     Also note that there may be a one-to-many relationship between
     `literal' and `lituse', but not a many-to-one.  That is, if there
     are two code paths that load up the same address and feed the
     value to a single use, then the use may not use a `lituse'
     relocation.

`!lituse_base!N'
     Used with any memory format instruction (e.g. `ldl') to indicate
     that the literal is used for an address load.  The offset field of
     the instruction must be zero.  During relaxation, the code may be
     altered to use a gp-relative load.

`!lituse_jsr!N'
     Used with a register branch format instruction (e.g. `jsr') to
     indicate that the literal is used for a call.  During relaxation,
     the code may be altered to use a direct branch (e.g. `bsr').

`!lituse_jsrdirect!N'
     Similar to `lituse_jsr', but also that this call cannot be vectored
     through a PLT entry.  This is useful for functions with special
     calling conventions which do not allow the normal call-clobbered
     registers to be clobbered.

`!lituse_bytoff!N'
     Used with a byte mask instruction (e.g. `extbl') to indicate that
     only the low 3 bits of the address are relevant.  During
     relaxation, the code may be altered to use an immediate instead of
     a register shift.

`!lituse_addr!N'
     Used with any other instruction to indicate that the original
     address is in fact used, and the original `ldq' instruction may
     not be altered or deleted.  This is useful in conjunction with
     `lituse_jsr' to test whether a weak symbol is defined.

          ldq  $27,foo($29)   !literal!1
          beq  $27,is_undef   !lituse_addr!1
          jsr  $26,($27),foo  !lituse_jsr!1

`!lituse_tlsgd!N'
     Used with a register branch format instruction to indicate that the
     literal is the call to `__tls_get_addr' used to compute the
     address of the thread-local storage variable whose descriptor was
     loaded with `!tlsgd!N'.

`!lituse_tlsldm!N'
     Used with a register branch format instruction to indicate that the
     literal is the call to `__tls_get_addr' used to compute the
     address of the base of the thread-local storage block for the
     current module.  The descriptor for the module must have been
     loaded with `!tlsldm!N'.

`!gpdisp!N'
     Used with `ldah' and `lda' to load the GP from the current
     address, a-la the `ldgp' macro.  The source register for the
     `ldah' instruction must contain the address of the `ldah'
     instruction.  There must be exactly one `lda' instruction paired
     with the `ldah' instruction, though it may appear anywhere in the
     instruction stream.  The immediate operands must be zero.

          bsr  $26,foo
          ldah $29,0($26)     !gpdisp!1
          lda  $29,0($29)     !gpdisp!1

`!gprelhigh'
     Used with an `ldah' instruction to add the high 16 bits of a
     32-bit displacement from the GP.

`!gprellow'
     Used with any memory format instruction to add the low 16 bits of a
     32-bit displacement from the GP.

`!gprel'
     Used with any memory format instruction to add a 16-bit
     displacement from the GP.

`!samegp'
     Used with any branch format instruction to skip the GP load at the
     target address.  The referenced symbol must have the same GP as the
     source object file, and it must be declared to either not use `$27'
     or perform a standard GP load in the first two instructions via the
     `.prologue' directive.

`!tlsgd'
`!tlsgd!N'
     Used with an `lda' instruction to load the address of a TLS
     descriptor for a symbol in the GOT.

     The sequence number N is optional, and if present it used to pair
     the descriptor load with both the `literal' loading the address of
     the `__tls_get_addr' function and the `lituse_tlsgd' marking the
     call to that function.

     For proper relaxation, both the `tlsgd', `literal' and `lituse'
     relocations must be in the same extended basic block.  That is,
     the relocation with the lowest address must be executed first at
     runtime.

`!tlsldm'
`!tlsldm!N'
     Used with an `lda' instruction to load the address of a TLS
     descriptor for the current module in the GOT.

     Similar in other respects to `tlsgd'.

`!gotdtprel'
     Used with an `ldq' instruction to load the offset of the TLS
     symbol within its module's thread-local storage block.  Also known
     as the dynamic thread pointer offset or dtp-relative offset.

`!dtprelhi'
`!dtprello'
`!dtprel'
     Like `gprel' relocations except they compute dtp-relative offsets.

`!gottprel'
     Used with an `ldq' instruction to load the offset of the TLS
     symbol from the thread pointer.  Also known as the tp-relative
     offset.

`!tprelhi'
`!tprello'
`!tprel'
     Like `gprel' relocations except they compute tp-relative offsets.


File: as.info,  Node: Alpha Floating Point,  Next: Alpha Directives,  Prev: Alpha Syntax,  Up: Alpha-Dependent

8.1.4 Floating Point
--------------------

The Alpha family uses both IEEE and VAX floating-point numbers.


File: as.info,  Node: Alpha Directives,  Next: Alpha Opcodes,  Prev: Alpha Floating Point,  Up: Alpha-Dependent

8.1.5 Alpha Assembler Directives
--------------------------------

`as' for the Alpha supports many additional directives for
compatibility with the native assembler.  This section describes them
only briefly.

   These are the additional directives in `as' for the Alpha:

`.arch CPU'
     Specifies the target processor.  This is equivalent to the `-mCPU'
     command-line option.  *Note Options: Alpha Options, for a list of
     values for CPU.

`.ent FUNCTION[, N]'
     Mark the beginning of FUNCTION.  An optional number may follow for
     compatibility with the OSF/1 assembler, but is ignored.  When
     generating `.mdebug' information, this will create a procedure
     descriptor for the function.  In ELF, it will mark the symbol as a
     function a-la the generic `.type' directive.

`.end FUNCTION'
     Mark the end of FUNCTION.  In ELF, it will set the size of the
     symbol a-la the generic `.size' directive.

`.mask MASK, OFFSET'
     Indicate which of the integer registers are saved in the current
     function's stack frame.  MASK is interpreted a bit mask in which
     bit N set indicates that register N is saved.  The registers are
     saved in a block located OFFSET bytes from the "canonical frame
     address" (CFA) which is the value of the stack pointer on entry to
     the function.  The registers are saved sequentially, except that
     the return address register (normally `$26') is saved first.

     This and the other directives that describe the stack frame are
     currently only used when generating `.mdebug' information.  They
     may in the future be used to generate DWARF2 `.debug_frame' unwind
     information for hand written assembly.

`.fmask MASK, OFFSET'
     Indicate which of the floating-point registers are saved in the
     current stack frame.  The MASK and OFFSET parameters are
     interpreted as with `.mask'.

`.frame FRAMEREG, FRAMEOFFSET, RETREG[, ARGOFFSET]'
     Describes the shape of the stack frame.  The frame pointer in use
     is FRAMEREG; normally this is either `$fp' or `$sp'.  The frame
     pointer is FRAMEOFFSET bytes below the CFA.  The return address is
     initially located in RETREG until it is saved as indicated in
     `.mask'.  For compatibility with OSF/1 an optional ARGOFFSET
     parameter is accepted and ignored.  It is believed to indicate the
     offset from the CFA to the saved argument registers.

`.prologue N'
     Indicate that the stack frame is set up and all registers have been
     spilled.  The argument N indicates whether and how the function
     uses the incoming "procedure vector" (the address of the called
     function) in `$27'.  0 indicates that `$27' is not used; 1
     indicates that the first two instructions of the function use `$27'
     to perform a load of the GP register; 2 indicates that `$27' is
     used in some non-standard way and so the linker cannot elide the
     load of the procedure vector during relaxation.

`.usepv FUNCTION, WHICH'
     Used to indicate the use of the `$27' register, similar to
     `.prologue', but without the other semantics of needing to be
     inside an open `.ent'/`.end' block.

     The WHICH argument should be either `no', indicating that `$27' is
     not used, or `std', indicating that the first two instructions of
     the function perform a GP load.

     One might use this directive instead of `.prologue' if you are
     also using dwarf2 CFI directives.

`.gprel32 EXPRESSION'
     Computes the difference between the address in EXPRESSION and the
     GP for the current object file, and stores it in 4 bytes.  In
     addition to being smaller than a full 8 byte address, this also
     does not require a dynamic relocation when used in a shared
     library.

`.t_floating EXPRESSION'
     Stores EXPRESSION as an IEEE double precision value.

`.s_floating EXPRESSION'
     Stores EXPRESSION as an IEEE single precision value.

`.f_floating EXPRESSION'
     Stores EXPRESSION as a VAX F format value.

`.g_floating EXPRESSION'
     Stores EXPRESSION as a VAX G format value.

`.d_floating EXPRESSION'
     Stores EXPRESSION as a VAX D format value.

`.set FEATURE'
     Enables or disables various assembler features.  Using the positive
     name of the feature enables while using `noFEATURE' disables.

    `at'
          Indicates that macro expansions may clobber the "assembler
          temporary" (`$at' or `$28') register.  Some macros may not be
          expanded without this and will generate an error message if
          `noat' is in effect.  When `at' is in effect, a warning will
          be generated if `$at' is used by the programmer.

    `macro'
          Enables the expansion of macro instructions.  Note that
          variants of real instructions, such as `br label' vs `br
          $31,label' are considered alternate forms and not macros.

    `move'
    `reorder'
    `volatile'
          These control whether and how the assembler may re-order
          instructions.  Accepted for compatibility with the OSF/1
          assembler, but `as' does not do instruction scheduling, so
          these features are ignored.

   The following directives are recognized for compatibility with the
OSF/1 assembler but are ignored.

     .proc           .aproc
     .reguse         .livereg
     .option         .aent
     .ugen           .eflag
     .alias          .noalias


File: as.info,  Node: Alpha Opcodes,  Prev: Alpha Directives,  Up: Alpha-Dependent

8.1.6 Opcodes
-------------

For detailed information on the Alpha machine instruction set, see the
Alpha Architecture Handbook
(ftp://ftp.digital.com/pub/Digital/info/semiconductor/literature/alphaahb.pdf).


File: as.info,  Node: ARC-Dependent,  Next: ARM-Dependent,  Prev: Alpha-Dependent,  Up: Machine Dependencies

8.2 ARC Dependent Features
==========================

* Menu:

* ARC Options::              Options
* ARC Syntax::               Syntax
* ARC Floating Point::       Floating Point
* ARC Directives::           ARC Machine Directives
* ARC Opcodes::              Opcodes


File: as.info,  Node: ARC Options,  Next: ARC Syntax,  Up: ARC-Dependent

8.2.1 Options
-------------

`-marc[5|6|7|8]'
     This option selects the core processor variant.  Using `-marc' is
     the same as `-marc6', which is also the default.

    `arc5'
          Base instruction set.

    `arc6'
          Jump-and-link (jl) instruction.  No requirement of an
          instruction between setting flags and conditional jump.  For
          example:

                 mov.f r0,r1
                 beq   foo

    `arc7'
          Break (brk) and sleep (sleep) instructions.

    `arc8'
          Software interrupt (swi) instruction.


     Note: the `.option' directive can to be used to select a core
     variant from within assembly code.

`-EB'
     This option specifies that the output generated by the assembler
     should be marked as being encoded for a big-endian processor.

`-EL'
     This option specifies that the output generated by the assembler
     should be marked as being encoded for a little-endian processor -
     this is the default.



File: as.info,  Node: ARC Syntax,  Next: ARC Floating Point,  Prev: ARC Options,  Up: ARC-Dependent

8.2.2 Syntax
------------

* Menu:

* ARC-Chars::                Special Characters
* ARC-Regs::                 Register Names


File: as.info,  Node: ARC-Chars,  Next: ARC-Regs,  Up: ARC Syntax

8.2.2.1 Special Characters
..........................

*TODO*


File: as.info,  Node: ARC-Regs,  Prev: ARC-Chars,  Up: ARC Syntax

8.2.2.2 Register Names
......................

*TODO*


File: as.info,  Node: ARC Floating Point,  Next: ARC Directives,  Prev: ARC Syntax,  Up: ARC-Dependent

8.2.3 Floating Point
--------------------

The ARC core does not currently have hardware floating point support.
Software floating point support is provided by `GCC' and uses IEEE
floating-point numbers.


File: as.info,  Node: ARC Directives,  Next: ARC Opcodes,  Prev: ARC Floating Point,  Up: ARC-Dependent

8.2.4 ARC Machine Directives
----------------------------

The ARC version of `as' supports the following additional machine
directives:

`.2byte EXPRESSIONS'
     *TODO*

`.3byte EXPRESSIONS'
     *TODO*

`.4byte EXPRESSIONS'
     *TODO*

`.extAuxRegister NAME,ADDRESS,MODE'
     The ARCtangent A4 has extensible auxiliary register space.  The
     auxiliary registers can be defined in the assembler source code by
     using this directive.  The first parameter is the NAME of the new
     auxiallry register.  The second parameter is the ADDRESS of the
     register in the auxiliary register memory map for the variant of
     the ARC.  The third parameter specifies the MODE in which the
     register can be operated is and it can be one of:

    `r          (readonly)'

    `w          (write only)'

    `r|w        (read or write)'

     For example:

            .extAuxRegister mulhi,0x12,w

     This specifies an extension auxiliary register called _mulhi_
     which is at address 0x12 in the memory space and which is only
     writable.

`.extCondCode SUFFIX,VALUE'
     The condition codes on the ARCtangent A4 are extensible and can be
     specified by means of this assembler directive.  They are specified
     by the suffix and the value for the condition code.  They can be
     used to specify extra condition codes with any values.  For
     example:

            .extCondCode is_busy,0x14

             add.is_busy  r1,r2,r3
             bis_busy     _main

`.extCoreRegister NAME,REGNUM,MODE,SHORTCUT'
     Specifies an extension core register NAME for the application.
     This allows a register NAME with a valid REGNUM between 0 and 60,
     with the following as valid values for MODE

    `_r_   (readonly)'

    `_w_   (write only)'

    `_r|w_ (read or write)'

     The other parameter gives a description of the register having a
     SHORTCUT in the pipeline.  The valid values are:

    `can_shortcut'

    `cannot_shortcut'

     For example:

            .extCoreRegister mlo,57,r,can_shortcut

     This defines an extension core register mlo with the value 57 which
     can shortcut the pipeline.

`.extInstruction NAME,OPCODE,SUBOPCODE,SUFFIXCLASS,SYNTAXCLASS'
     The ARCtangent A4 allows the user to specify extension
     instructions.  The extension instructions are not macros.  The
     assembler creates encodings for use of these instructions
     according to the specification by the user.  The parameters are:

    *NAME
          Name of the extension instruction

    *OPCODE
          Opcode to be used. (Bits 27:31 in the encoding).  Valid values
          0x10-0x1f or 0x03

    *SUBOPCODE
          Subopcode to be used.  Valid values are from 0x09-0x3f.
          However the correct value also depends on SYNTAXCLASS

    *SUFFIXCLASS
          Determines the kinds of suffixes to be allowed.  Valid values
          are `SUFFIX_NONE', `SUFFIX_COND', `SUFFIX_FLAG' which
          indicates the absence or presence of conditional suffixes and
          flag setting by the extension instruction.  It is also
          possible to specify that an instruction sets the flags and is
          conditional by using `SUFFIX_CODE' | `SUFFIX_FLAG'.

    *SYNTAXCLASS
          Determines the syntax class for the instruction.  It can have
          the following values:

         ``SYNTAX_2OP':'
               2 Operand Instruction

         ``SYNTAX_3OP':'
               3 Operand Instruction

          In addition there could be modifiers for the syntax class as
          described below:

               Syntax Class Modifiers are:

             - `OP1_MUST_BE_IMM': Modifies syntax class SYNTAX_3OP,
               specifying that the first operand of a three-operand
               instruction must be an immediate (i.e. the result is
               discarded).  OP1_MUST_BE_IMM is used by bitwise ORing it
               with SYNTAX_3OP as given in the example below.  This
               could usually be used to set the flags using specific
               instructions and not retain results.

             - `OP1_IMM_IMPLIED': Modifies syntax class SYNTAX_20P, it
               specifies that there is an implied immediate destination
               operand which does not appear in the syntax.  For
               example, if the source code contains an instruction like:

                    inst r1,r2

               it really means that the first argument is an implied
               immediate (that is, the result is discarded).  This is
               the same as though the source code were: inst 0,r1,r2.
               You use OP1_IMM_IMPLIED by bitwise ORing it with
               SYNTAX_20P.


     For example, defining 64-bit multiplier with immediate operands:

          .extInstruction mp64,0x14,0x0,SUFFIX_COND | SUFFIX_FLAG ,
                          SYNTAX_3OP|OP1_MUST_BE_IMM

     The above specifies an extension instruction called mp64 which has
     3 operands, sets the flags, can be used with a condition code, for
     which the first operand is an immediate.  (Equivalent to
     discarding the result of the operation).

           .extInstruction mul64,0x14,0x00,SUFFIX_COND, SYNTAX_2OP|OP1_IMM_IMPLIED

     This describes a 2 operand instruction with an implicit first
     immediate operand.  The result of this operation would be
     discarded.

`.half EXPRESSIONS'
     *TODO*

`.long EXPRESSIONS'
     *TODO*

`.option ARC|ARC5|ARC6|ARC7|ARC8'
     The `.option' directive must be followed by the desired core
     version. Again `arc' is an alias for `arc6'.

     Note: the `.option' directive overrides the command line option
     `-marc'; a warning is emitted when the version is not consistent
     between the two - even for the implicit default core version
     (arc6).

`.short EXPRESSIONS'
     *TODO*

`.word EXPRESSIONS'
     *TODO*



File: as.info,  Node: ARC Opcodes,  Prev: ARC Directives,  Up: ARC-Dependent

8.2.5 Opcodes
-------------

For information on the ARC instruction set, see `ARC Programmers
Reference Manual', ARC International (www.arc.com)


File: as.info,  Node: ARM-Dependent,  Next: BFIN-Dependent,  Prev: ARC-Dependent,  Up: Machine Dependencies

8.3 ARM Dependent Features
==========================

* Menu:

* ARM Options::              Options
* ARM Syntax::               Syntax
* ARM Floating Point::       Floating Point
* ARM Directives::           ARM Machine Directives
* ARM Opcodes::              Opcodes
* ARM Mapping Symbols::      Mapping Symbols


File: as.info,  Node: ARM Options,  Next: ARM Syntax,  Up: ARM-Dependent

8.3.1 Options
-------------

`-mcpu=PROCESSOR[+EXTENSION...]'
     This option specifies the target processor.  The assembler will
     issue an error message if an attempt is made to assemble an
     instruction which will not execute on the target processor.  The
     following processor names are recognized: `arm1', `arm2', `arm250',
     `arm3', `arm6', `arm60', `arm600', `arm610', `arm620', `arm7',
     `arm7m', `arm7d', `arm7dm', `arm7di', `arm7dmi', `arm70', `arm700',
     `arm700i', `arm710', `arm710t', `arm720', `arm720t', `arm740t',
     `arm710c', `arm7100', `arm7500', `arm7500fe', `arm7t', `arm7tdmi',
     `arm7tdmi-s', `arm8', `arm810', `strongarm', `strongarm1',
     `strongarm110', `strongarm1100', `strongarm1110', `arm9', `arm920',
     `arm920t', `arm922t', `arm940t', `arm9tdmi', `arm9e', `arm926e',
     `arm926ej-s', `arm946e-r0', `arm946e', `arm946e-s', `arm966e-r0',
     `arm966e', `arm966e-s', `arm968e-s', `arm10t', `arm10tdmi',
     `arm10e', `arm1020', `arm1020t', `arm1020e', `arm1022e',
     `arm1026ej-s', `arm1136j-s', `arm1136jf-s', `arm1156t2-s',
     `arm1156t2f-s', `arm1176jz-s', `arm1176jzf-s', `mpcore',
     `mpcorenovfp', `cortex-a8', `cortex-r4', `cortex-m3', `ep9312'
     (ARM920 with Cirrus Maverick coprocessor), `i80200' (Intel XScale
     processor) `iwmmxt' (Intel(r) XScale processor with Wireless
     MMX(tm) technology coprocessor) and `xscale'.  The special name
     `all' may be used to allow the assembler to accept instructions
     valid for any ARM processor.

     In addition to the basic instruction set, the assembler can be
     told to accept various extension mnemonics that extend the
     processor using the co-processor instruction space.  For example,
     `-mcpu=arm920+maverick' is equivalent to specifying
     `-mcpu=ep9312'.  The following extensions are currently supported:
     `+maverick' `+iwmmxt' and `+xscale'.

`-march=ARCHITECTURE[+EXTENSION...]'
     This option specifies the target architecture.  The assembler will
     issue an error message if an attempt is made to assemble an
     instruction which will not execute on the target architecture.
     The following architecture names are recognized: `armv1', `armv2',
     `armv2a', `armv2s', `armv3', `armv3m', `armv4', `armv4xm',
     `armv4t', `armv4txm', `armv5', `armv5t', `armv5txm', `armv5te',
     `armv5texp', `armv6', `armv6j', `armv6k', `armv6z', `armv6zk',
     `armv7', `armv7a', `armv7r', `armv7m', `iwmmxt' and `xscale'.  If
     both `-mcpu' and `-march' are specified, the assembler will use
     the setting for `-mcpu'.

     The architecture option can be extended with the same instruction
     set extension options as the `-mcpu' option.

`-mfpu=FLOATING-POINT-FORMAT'
     This option specifies the floating point format to assemble for.
     The assembler will issue an error message if an attempt is made to
     assemble an instruction which will not execute on the target
     floating point unit.  The following format options are recognized:
     `softfpa', `fpe', `fpe2', `fpe3', `fpa', `fpa10', `fpa11',
     `arm7500fe', `softvfp', `softvfp+vfp', `vfp', `vfp10', `vfp10-r0',
     `vfp9', `vfpxd', `arm1020t', `arm1020e', `arm1136jf-s' and
     `maverick'.

     In addition to determining which instructions are assembled, this
     option also affects the way in which the `.double' assembler
     directive behaves when assembling little-endian code.

     The default is dependent on the processor selected.  For
     Architecture 5 or later, the default is to assembler for VFP
     instructions; for earlier architectures the default is to assemble
     for FPA instructions.

`-mthumb'
     This option specifies that the assembler should start assembling
     Thumb instructions; that is, it should behave as though the file
     starts with a `.code 16' directive.

`-mthumb-interwork'
     This option specifies that the output generated by the assembler
     should be marked as supporting interworking.

`-mapcs `[26|32]''
     This option specifies that the output generated by the assembler
     should be marked as supporting the indicated version of the Arm
     Procedure.  Calling Standard.

`-matpcs'
     This option specifies that the output generated by the assembler
     should be marked as supporting the Arm/Thumb Procedure Calling
     Standard.  If enabled this option will cause the assembler to
     create an empty debugging section in the object file called
     .arm.atpcs.  Debuggers can use this to determine the ABI being
     used by.

`-mapcs-float'
     This indicates the floating point variant of the APCS should be
     used.  In this variant floating point arguments are passed in FP
     registers rather than integer registers.

`-mapcs-reentrant'
     This indicates that the reentrant variant of the APCS should be
     used.  This variant supports position independent code.

`-mfloat-abi=ABI'
     This option specifies that the output generated by the assembler
     should be marked as using specified floating point ABI.  The
     following values are recognized: `soft', `softfp' and `hard'.

`-meabi=VER'
     This option specifies which EABI version the produced object files
     should conform to.  The following values are recognised: `gnu', `4'
     and `5'.

`-EB'
     This option specifies that the output generated by the assembler
     should be marked as being encoded for a big-endian processor.

`-EL'
     This option specifies that the output generated by the assembler
     should be marked as being encoded for a little-endian processor.

`-k'
     This option specifies that the output of the assembler should be
     marked as position-independent code (PIC).



File: as.info,  Node: ARM Syntax,  Next: ARM Floating Point,  Prev: ARM Options,  Up: ARM-Dependent

8.3.2 Syntax
------------

* Menu:

* ARM-Chars::                Special Characters
* ARM-Regs::                 Register Names


File: as.info,  Node: ARM-Chars,  Next: ARM-Regs,  Up: ARM Syntax

8.3.2.1 Special Characters
..........................

The presence of a `@' on a line indicates the start of a comment that
extends to the end of the current line.  If a `#' appears as the first
character of a line, the whole line is treated as a comment.

   The `;' character can be used instead of a newline to separate
statements.

   Either `#' or `$' can be used to indicate immediate operands.

   *TODO* Explain about /data modifier on symbols.


File: as.info,  Node: ARM-Regs,  Prev: ARM-Chars,  Up: ARM Syntax

8.3.2.2 Register Names
......................

*TODO* Explain about ARM register naming, and the predefined names.


File: as.info,  Node: ARM Floating Point,  Next: ARM Directives,  Prev: ARM Syntax,  Up: ARM-Dependent

8.3.3 Floating Point
--------------------

The ARM family uses IEEE floating-point numbers.


File: as.info,  Node: ARM Directives,  Next: ARM Opcodes,  Prev: ARM Floating Point,  Up: ARM-Dependent

8.3.4 ARM Machine Directives
----------------------------

`.align EXPRESSION [, EXPRESSION]'
     This is the generic .ALIGN directive.  For the ARM however if the
     first argument is zero (ie no alignment is needed) the assembler
     will behave as if the argument had been 2 (ie pad to the next four
     byte boundary).  This is for compatibility with ARM's own
     assembler.

`NAME .req REGISTER NAME'
     This creates an alias for REGISTER NAME called NAME.  For example:

                  foo .req r0

`.unreq ALIAS-NAME'
     This undefines a register alias which was previously defined using
     the `req' directive.  For example:

                  foo .req r0
                  .unreq foo

     An error occurs if the name is undefined.  Note - this pseudo op
     can be used to delete builtin in register name aliases (eg 'r0').
     This should only be done if it is really necessary.

`.code `[16|32]''
     This directive selects the instruction set being generated. The
     value 16 selects Thumb, with the value 32 selecting ARM.

`.thumb'
     This performs the same action as .CODE 16.

`.arm'
     This performs the same action as .CODE 32.

`.force_thumb'
     This directive forces the selection of Thumb instructions, even if
     the target processor does not support those instructions

`.thumb_func'
     This directive specifies that the following symbol is the name of a
     Thumb encoded function.  This information is necessary in order to
     allow the assembler and linker to generate correct code for
     interworking between Arm and Thumb instructions and should be used
     even if interworking is not going to be performed.  The presence
     of this directive also implies `.thumb'

`.thumb_set'
     This performs the equivalent of a `.set' directive in that it
     creates a symbol which is an alias for another symbol (possibly
     not yet defined).  This directive also has the added property in
     that it marks the aliased symbol as being a thumb function entry
     point, in the same way that the `.thumb_func' directive does.

`.ltorg'
     This directive causes the current contents of the literal pool to
     be dumped into the current section (which is assumed to be the
     .text section) at the current location (aligned to a word
     boundary).  `GAS' maintains a separate literal pool for each
     section and each sub-section.  The `.ltorg' directive will only
     affect the literal pool of the current section and sub-section.
     At the end of assembly all remaining, un-empty literal pools will
     automatically be dumped.

     Note - older versions of `GAS' would dump the current literal pool
     any time a section change occurred.  This is no longer done, since
     it prevents accurate control of the placement of literal pools.

`.pool'
     This is a synonym for .ltorg.

`.unwind_fnstart'
     Marks the start of a function with an unwind table entry.

`.unwind_fnend'
     Marks the end of a function with an unwind table entry.  The
     unwind index table entry is created when this directive is
     processed.

     If no personality routine has been specified then standard
     personality routine 0 or 1 will be used, depending on the number
     of unwind opcodes required.

`.cantunwind'
     Prevents unwinding through the current function.  No personality
     routine or exception table data is required or permitted.

`.personality NAME'
     Sets the personality routine for the current function to NAME.

`.personalityindex INDEX'
     Sets the personality routine for the current function to the EABI
     standard routine number INDEX

`.handlerdata'
     Marks the end of the current function, and the start of the
     exception table entry for that function.  Anything between this
     directive and the `.fnend' directive will be added to the
     exception table entry.

     Must be preceded by a `.personality' or `.personalityindex'
     directive.

`.save REGLIST'
     Generate unwinder annotations to restore the registers in REGLIST.
     The format of REGLIST is the same as the corresponding
     store-multiple instruction.

     _core registers_
            .save {r4, r5, r6, lr}
            stmfd sp!, {r4, r5, r6, lr}
     _FPA registers_
            .save f4, 2
            sfmfd f4, 2, [sp]!
     _VFP registers_
            .save {d8, d9, d10}
            fstmdf sp!, {d8, d9, d10}
     _iWMMXt registers_
            .save {wr10, wr11}
            wstrd wr11, [sp, #-8]!
            wstrd wr10, [sp, #-8]!
          or
            .save wr11
            wstrd wr11, [sp, #-8]!
            .save wr10
            wstrd wr10, [sp, #-8]!

`.pad #COUNT'
     Generate unwinder annotations for a stack adjustment of COUNT
     bytes.  A positive value indicates the function prologue allocated
     stack space by decrementing the stack pointer.

`.movsp REG'
     Tell the unwinder that REG contains the current stack pointer.

`.setfp FPREG, SPREG [, #OFFSET]'
     Make all unwinder annotations relaive to a frame pointer.  Without
     this the unwinder will use offsets from the stack pointer.

     The syntax of this directive is the same as the `sub' or `mov'
     instruction used to set the frame pointer.  SPREG must be either
     `sp' or mentioned in a previous `.movsp' directive.

          .movsp ip
          mov ip, sp
          ...
          .setfp fp, ip, #4
          sub fp, ip, #4

`.raw OFFSET, BYTE1, ...'
     Insert one of more arbitary unwind opcode bytes, which are known
     to adjust the stack pointer by OFFSET bytes.

     For example `.unwind_raw 4, 0xb1, 0x01' is equivalent to `.save
     {r0}'

`.cpu NAME'
     Select the target processor.  Valid values for NAME are the same as
     for the `-mcpu' commandline option.

`.arch NAME'
     Select the target architecture.  Valid values for NAME are the
     same as for the `-march' commandline option.

`.fpu NAME'
     Select the floating point unit to assemble for.  Valid values for
     NAME are the same as for the `-mfpu' commandline option.

`.eabi_attribute TAG, VALUE'
     Set the EABI object attribute number TAG to VALUE.  The value is
     either a `number', `"string"', or `number, "string"' depending on
     the tag.



File: as.info,  Node: ARM Opcodes,  Next: ARM Mapping Symbols,  Prev: ARM Directives,  Up: ARM-Dependent

8.3.5 Opcodes
-------------

`as' implements all the standard ARM opcodes.  It also implements
several pseudo opcodes, including several synthetic load instructions.

`NOP'
            nop

     This pseudo op will always evaluate to a legal ARM instruction
     that does nothing.  Currently it will evaluate to MOV r0, r0.

`LDR'
            ldr <register> , = <expression>

     If expression evaluates to a numeric constant then a MOV or MVN
     instruction will be used in place of the LDR instruction, if the
     constant can be generated by either of these instructions.
     Otherwise the constant will be placed into the nearest literal
     pool (if it not already there) and a PC relative LDR instruction
     will be generated.

`ADR'
            adr <register> <label>

     This instruction will load the address of LABEL into the indicated
     register.  The instruction will evaluate to a PC relative ADD or
     SUB instruction depending upon where the label is located.  If the
     label is out of range, or if it is not defined in the same file
     (and section) as the ADR instruction, then an error will be
     generated.  This instruction will not make use of the literal pool.

`ADRL'
            adrl <register> <label>

     This instruction will load the address of LABEL into the indicated
     register.  The instruction will evaluate to one or two PC relative
     ADD or SUB instructions depending upon where the label is located.
     If a second instruction is not needed a NOP instruction will be
     generated in its place, so that this instruction is always 8 bytes
     long.

     If the label is out of range, or if it is not defined in the same
     file (and section) as the ADRL instruction, then an error will be
     generated.  This instruction will not make use of the literal pool.


   For information on the ARM or Thumb instruction sets, see `ARM
Software Development Toolkit Reference Manual', Advanced RISC Machines
Ltd.


File: as.info,  Node: ARM Mapping Symbols,  Prev: ARM Opcodes,  Up: ARM-Dependent

8.3.6 Mapping Symbols
---------------------

The ARM ELF specification requires that special symbols be inserted
into object files to mark certain features:

`$a'
     At the start of a region of code containing ARM instructions.

`$t'
     At the start of a region of code containing THUMB instructions.

`$d'
     At the start of a region of data.


   The assembler will automatically insert these symbols for you - there
is no need to code them yourself.  Support for tagging symbols ($b, $f,
$p and $m) which is also mentioned in the current ARM ELF specification
is not implemented.  This is because they have been dropped from the
new EABI and so tools cannot rely upon their presence.


File: as.info,  Node: BFIN-Dependent,  Next: CRIS-Dependent,  Prev: ARM-Dependent,  Up: Machine Dependencies

8.4 Blackfin Dependent Features
===============================

* Menu:

* BFIN Syntax::			BFIN Syntax
* BFIN Directives::		BFIN Directives


File: as.info,  Node: BFIN Syntax,  Next: BFIN Directives,  Up: BFIN-Dependent

8.4.1 Syntax
------------

`Special Characters'
     Assembler input is free format and may appear anywhere on the line.
     One instruction may extend across multiple lines or more than one
     instruction may appear on the same line.  White space (space, tab,
     comments or newline) may appear anywhere between tokens.  A token
     must not have embedded spaces.  Tokens include numbers, register
     names, keywords, user identifiers, and also some multicharacter
     special symbols like "+=", "/*" or "||".

`Instruction Delimiting'
     A semicolon must terminate every instruction.  Sometimes a complete
     instruction will consist of more than one operation.  There are two
     cases where this occurs.  The first is when two general operations
     are combined.  Normally a comma separates the different parts, as
     in

          a0= r3.h * r2.l, a1 = r3.l * r2.h ;

     The second case occurs when a general instruction is combined with
     one or two memory references for joint issue.  The latter portions
     are set off by a "||" token.

          a0 = r3.h * r2.l || r1 = [p3++] || r4 = [i2++];

`Register Names'
     The assembler treats register names and instruction keywords in a
     case insensitive manner.  User identifiers are case sensitive.
     Thus, R3.l, R3.L, r3.l and r3.L are all equivalent input to the
     assembler.

     Register names are reserved and may not be used as program
     identifiers.

     Some operations (such as "Move Register") require a register pair.
     Register pairs are always data registers and are denoted using a
     colon, eg., R3:2.  The larger number must be written firsts.  Note
     that the hardware only supports odd-even pairs, eg., R7:6, R5:4,
     R3:2, and R1:0.

     Some instructions (such as -SP (Push Multiple)) require a group of
     adjacent registers.  Adjacent registers are denoted in the syntax
     by the range enclosed in parentheses and separated by a colon,
     eg., (R7:3).  Again, the larger number appears first.

     Portions of a particular register may be individually specified.
     This is written with a dot (".") following the register name and
     then a letter denoting the desired portion.  For 32-bit registers,
     ".H" denotes the most significant ("High") portion.  ".L" denotes
     the least-significant portion.  The subdivisions of the 40-bit
     registers are described later.

`Accumulators'
     The set of 40-bit registers A1 and A0 that normally contain data
     that is being manipulated.  Each accumulator can be accessed in
     four ways.

    `one 40-bit register'
          The register will be referred to as A1 or A0.

    `one 32-bit register'
          The registers are designated as A1.W or A0.W.

    `two 16-bit registers'
          The registers are designated as A1.H, A1.L, A0.H or A0.L.

    `one 8-bit register'
          The registers are designated as A1.X or A0.X for the bits that
          extend beyond bit 31.

`Data Registers'
     The set of 32-bit registers (R0, R1, R2, R3, R4, R5, R6 and R7)
     that normally contain data for manipulation.  These are
     abbreviated as D-register or Dreg.  Data registers can be accessed
     as 32-bit registers or as two independent 16-bit registers.  The
     least significant 16 bits of each register is called the "low"
     half and is desginated with ".L" following the register name.  The
     most significant 16 bits are called the "high" half and is
     designated with ".H". following the name.

             R7.L, r2.h, r4.L, R0.H

`Pointer Registers'
     The set of 32-bit registers (P0, P1, P2, P3, P4, P5, SP and FP)
     that normally contain byte addresses of data structures.  These are
     abbreviated as P-register or Preg.

          p2, p5, fp, sp

`Stack Pointer SP'
     The stack pointer contains the 32-bit address of the last occupied
     byte location in the stack.  The stack grows by decrementing the
     stack pointer.

`Frame Pointer FP'
     The frame pointer contains the 32-bit address of the previous frame
     pointer in the stack.  It is located at the top of a frame.

`Loop Top'
     LT0 and LT1.  These registers contain the 32-bit address of the
     top of a zero overhead loop.

`Loop Count'
     LC0 and LC1.  These registers contain the 32-bit counter of the
     zero overhead loop executions.

`Loop Bottom'
     LB0 and LB1.  These registers contain the 32-bit address of the
     bottom of a zero overhead loop.

`Index Registers'
     The set of 32-bit registers (I0, I1, I2, I3) that normally contain
     byte addresses of data structures.  Abbreviated I-register or Ireg.

`Modify Registers'
     The set of 32-bit registers (M0, M1, M2, M3) that normally contain
     offset values that are added and subracted to one of the index
     registers.  Abbreviated as Mreg.

`Length Registers'
     The set of 32-bit registers (L0, L1, L2, L3) that normally contain
     the length in bytes of the circular buffer.  Abbreviated as Lreg.
     Clear the Lreg to disable circular addressing for the
     corresponding Ireg.

`Base Registers'
     The set of 32-bit registers (B0, B1, B2, B3) that normally contain
     the base address in bytes of the circular buffer.  Abbreviated as
     Breg.

`Floating Point'
     The Blackfin family has no hardware floating point but the .float
     directive generates ieee floating point numbers for use with
     software floating point libraries.

`Blackfin Opcodes'
     For detailed information on the Blackfin machine instruction set,
     see the Blackfin(r) Processor Instruction Set Reference.



File: as.info,  Node: BFIN Directives,  Prev: BFIN Syntax,  Up: BFIN-Dependent

8.4.2 Directives
----------------

The following directives are provided for compatibility with the VDSP
assembler.

`.byte2'
     Initializes a four byte data object.

`.byte4'
     Initializes a two byte data object.

`.db'
     TBD

`.dd'
     TBD

`.dw'
     TBD

`.var'
     Define and initialize a 32 bit data object.


File: as.info,  Node: CRIS-Dependent,  Next: D10V-Dependent,  Prev: BFIN-Dependent,  Up: Machine Dependencies

8.5 CRIS Dependent Features
===========================

* Menu:

* CRIS-Opts::              Command-line Options
* CRIS-Expand::            Instruction expansion
* CRIS-Symbols::           Symbols
* CRIS-Syntax::            Syntax


File: as.info,  Node: CRIS-Opts,  Next: CRIS-Expand,  Up: CRIS-Dependent

8.5.1 Command-line Options
--------------------------

The CRIS version of `as' has these machine-dependent command-line
options.

   The format of the generated object files can be either ELF or a.out,
specified by the command-line options `--emulation=crisaout' and
`--emulation=criself'.  The default is ELF (criself), unless `as' has
been configured specifically for a.out by using the configuration name
`cris-axis-aout'.

   There are two different link-incompatible ELF object file variants
for CRIS, for use in environments where symbols are expected to be
prefixed by a leading `_' character and for environments without such a
symbol prefix.  The variant used for GNU/Linux port has no symbol
prefix.  Which variant to produce is specified by either of the options
`--underscore' and `--no-underscore'.  The default is `--underscore'.
Since symbols in CRIS a.out objects are expected to have a `_' prefix,
specifying `--no-underscore' when generating a.out objects is an error.
Besides the object format difference, the effect of this option is to
parse register names differently (*note crisnous::).  The
`--no-underscore' option makes a `$' register prefix mandatory.

   The option `--pic' must be passed to `as' in order to recognize the
symbol syntax used for ELF (SVR4 PIC) position-independent-code (*note
crispic::).  This will also affect expansion of instructions.  The
expansion with `--pic' will use PC-relative rather than (slightly
faster) absolute addresses in those expansions.

   The option `--march=ARCHITECTURE' specifies the recognized
instruction set and recognized register names.  It also controls the
architecture type of the object file.  Valid values for ARCHITECTURE
are:
`v0_v10'
     All instructions and register names for any architecture variant
     in the set v0...v10 are recognized.  This is the default if the
     target is configured as cris-*.

`v10'
     Only instructions and register names for CRIS v10 (as found in
     ETRAX 100 LX) are recognized.  This is the default if the target
     is configured as crisv10-*.

`v32'
     Only instructions and register names for CRIS v32 (code name
     Guinness) are recognized.  This is the default if the target is
     configured as crisv32-*.  This value implies `--no-mul-bug-abort'.
     (A subsequent `--mul-bug-abort' will turn it back on.)

`common_v10_v32'
     Only instructions with register names and addressing modes with
     opcodes common to the v10 and v32 are recognized.

   When `-N' is specified, `as' will emit a warning when a 16-bit
branch instruction is expanded into a 32-bit multiple-instruction
construct (*note CRIS-Expand::).

   Some versions of the CRIS v10, for example in the Etrax 100 LX,
contain a bug that causes destabilizing memory accesses when a multiply
instruction is executed with certain values in the first operand just
before a cache-miss.  When the `--mul-bug-abort' command line option is
active (the default value), `as' will refuse to assemble a file
containing a multiply instruction at a dangerous offset, one that could
be the last on a cache-line, or is in a section with insufficient
alignment.  This placement checking does not catch any case where the
multiply instruction is dangerously placed because it is located in a
delay-slot.  The `--mul-bug-abort' command line option turns off the
checking.


File: as.info,  Node: CRIS-Expand,  Next: CRIS-Symbols,  Prev: CRIS-Opts,  Up: CRIS-Dependent

8.5.2 Instruction expansion
---------------------------

`as' will silently choose an instruction that fits the operand size for
`[register+constant]' operands.  For example, the offset `127' in
`move.d [r3+127],r4' fits in an instruction using a signed-byte offset.
Similarly, `move.d [r2+32767],r1' will generate an instruction using a
16-bit offset.  For symbolic expressions and constants that do not fit
in 16 bits including the sign bit, a 32-bit offset is generated.

   For branches, `as' will expand from a 16-bit branch instruction into
a sequence of instructions that can reach a full 32-bit address.  Since
this does not correspond to a single instruction, such expansions can
optionally be warned about.  *Note CRIS-Opts::.

   If the operand is found to fit the range, a `lapc' mnemonic will
translate to a `lapcq' instruction.  Use `lapc.d' to force the 32-bit
`lapc' instruction.

   Similarly, the `addo' mnemonic will translate to the shortest
fitting instruction of `addoq', `addo.w' and `addo.d', when used with a
operand that is a constant known at assembly time.


File: as.info,  Node: CRIS-Symbols,  Next: CRIS-Syntax,  Prev: CRIS-Expand,  Up: CRIS-Dependent

8.5.3 Symbols
-------------

Some symbols are defined by the assembler.  They're intended to be used
in conditional assembly, for example:
      .if ..asm.arch.cris.v32
      CODE FOR CRIS V32
      .elseif ..asm.arch.cris.common_v10_v32
      CODE COMMON TO CRIS V32 AND CRIS V10
      .elseif ..asm.arch.cris.v10 | ..asm.arch.cris.any_v0_v10
      CODE FOR V10
      .else
      .error "Code needs to be added here."
      .endif

   These symbols are defined in the assembler, reflecting command-line
options, either when specified or the default.  They are always
defined, to 0 or 1.
`..asm.arch.cris.any_v0_v10'
     This symbol is non-zero when `--march=v0_v10' is specified or the
     default.

`..asm.arch.cris.common_v10_v32'
     Set according to the option `--march=common_v10_v32'.

`..asm.arch.cris.v10'
     Reflects the option `--march=v10'.

`..asm.arch.cris.v32'
     Corresponds to `--march=v10'.

   Speaking of symbols, when a symbol is used in code, it can have a
suffix modifying its value for use in position-independent code. *Note
CRIS-Pic::.


File: as.info,  Node: CRIS-Syntax,  Prev: CRIS-Symbols,  Up: CRIS-Dependent

8.5.4 Syntax
------------

There are different aspects of the CRIS assembly syntax.

* Menu:

* CRIS-Chars::		        Special Characters
* CRIS-Pic::			Position-Independent Code Symbols
* CRIS-Regs::			Register Names
* CRIS-Pseudos::		Assembler Directives


File: as.info,  Node: CRIS-Chars,  Next: CRIS-Pic,  Up: CRIS-Syntax

8.5.4.1 Special Characters
..........................

The character `#' is a line comment character.  It starts a comment if
and only if it is placed at the beginning of a line.

   A `;' character starts a comment anywhere on the line, causing all
characters up to the end of the line to be ignored.

   A `@' character is handled as a line separator equivalent to a
logical new-line character (except in a comment), so separate
instructions can be specified on a single line.


File: as.info,  Node: CRIS-Pic,  Next: CRIS-Regs,  Prev: CRIS-Chars,  Up: CRIS-Syntax

8.5.4.2 Symbols in position-independent code
............................................

When generating position-independent code (SVR4 PIC) for use in
cris-axis-linux-gnu or crisv32-axis-linux-gnu shared libraries, symbol
suffixes are used to specify what kind of run-time symbol lookup will
be used, expressed in the object as different _relocation types_.
Usually, all absolute symbol values must be located in a table, the
_global offset table_, leaving the code position-independent;
independent of values of global symbols and independent of the address
of the code.  The suffix modifies the value of the symbol, into for
example an index into the global offset table where the real symbol
value is entered, or a PC-relative value, or a value relative to the
start of the global offset table.  All symbol suffixes start with the
character `:' (omitted in the list below).  Every symbol use in code or
a read-only section must therefore have a PIC suffix to enable a useful
shared library to be created.  Usually, these constructs must not be
used with an additive constant offset as is usually allowed, i.e. no 4
as in `symbol + 4' is allowed.  This restriction is checked at
link-time, not at assembly-time.

`GOT'
     Attaching this suffix to a symbol in an instruction causes the
     symbol to be entered into the global offset table.  The value is a
     32-bit index for that symbol into the global offset table.  The
     name of the corresponding relocation is `R_CRIS_32_GOT'.  Example:
     `move.d [$r0+extsym:GOT],$r9'

`GOT16'
     Same as for `GOT', but the value is a 16-bit index into the global
     offset table.  The corresponding relocation is `R_CRIS_16_GOT'.
     Example: `move.d [$r0+asymbol:GOT16],$r10'

`PLT'
     This suffix is used for function symbols.  It causes a _procedure
     linkage table_, an array of code stubs, to be created at the time
     the shared object is created or linked against, together with a
     global offset table entry.  The value is a pc-relative offset to
     the corresponding stub code in the procedure linkage table.  This
     arrangement causes the run-time symbol resolver to be called to
     look up and set the value of the symbol the first time the
     function is called (at latest; depending environment variables).
     It is only safe to leave the symbol unresolved this way if all
     references are function calls.  The name of the relocation is
     `R_CRIS_32_PLT_PCREL'.  Example: `add.d fnname:PLT,$pc'

`PLTG'
     Like PLT, but the value is relative to the beginning of the global
     offset table.  The relocation is `R_CRIS_32_PLT_GOTREL'.  Example:
     `move.d fnname:PLTG,$r3'

`GOTPLT'
     Similar to `PLT', but the value of the symbol is a 32-bit index
     into the global offset table.  This is somewhat of a mix between
     the effect of the `GOT' and the `PLT' suffix; the difference to
     `GOT' is that there will be a procedure linkage table entry
     created, and that the symbol is assumed to be a function entry and
     will be resolved by the run-time resolver as with `PLT'.  The
     relocation is `R_CRIS_32_GOTPLT'.  Example: `jsr
     [$r0+fnname:GOTPLT]'

`GOTPLT16'
     A variant of `GOTPLT' giving a 16-bit value.  Its relocation name
     is `R_CRIS_16_GOTPLT'.  Example: `jsr [$r0+fnname:GOTPLT16]'

`GOTOFF'
     This suffix must only be attached to a local symbol, but may be
     used in an expression adding an offset.  The value is the address
     of the symbol relative to the start of the global offset table.
     The relocation name is `R_CRIS_32_GOTREL'.  Example: `move.d
     [$r0+localsym:GOTOFF],r3'


File: as.info,  Node: CRIS-Regs,  Next: CRIS-Pseudos,  Prev: CRIS-Pic,  Up: CRIS-Syntax

8.5.4.3 Register names
......................

A `$' character may always prefix a general or special register name in
an instruction operand but is mandatory when the option
`--no-underscore' is specified or when the `.syntax register_prefix'
directive is in effect (*note crisnous::).  Register names are
case-insensitive.


File: as.info,  Node: CRIS-Pseudos,  Prev: CRIS-Regs,  Up: CRIS-Syntax

8.5.4.4 Assembler Directives
............................

There are a few CRIS-specific pseudo-directives in addition to the
generic ones.  *Note Pseudo Ops::.  Constants emitted by
pseudo-directives are in little-endian order for CRIS.  There is no
support for floating-point-specific directives for CRIS.

`.dword EXPRESSIONS'
     The `.dword' directive is a synonym for `.int', expecting zero or
     more EXPRESSIONS, separated by commas.  For each expression, a
     32-bit little-endian constant is emitted.

`.syntax ARGUMENT'
     The `.syntax' directive takes as ARGUMENT one of the following
     case-sensitive choices.

    `no_register_prefix'
          The `.syntax no_register_prefix' directive makes a `$'
          character prefix on all registers optional.  It overrides a
          previous setting, including the corresponding effect of the
          option `--no-underscore'.  If this directive is used when
          ordinary symbols do not have a `_' character prefix, care
          must be taken to avoid ambiguities whether an operand is a
          register or a symbol; using symbols with names the same as
          general or special registers then invoke undefined behavior.

    `register_prefix'
          This directive makes a `$' character prefix on all registers
          mandatory.  It overrides a previous setting, including the
          corresponding effect of the option `--underscore'.

    `leading_underscore'
          This is an assertion directive, emitting an error if the
          `--no-underscore' option is in effect.

    `no_leading_underscore'
          This is the opposite of the `.syntax leading_underscore'
          directive and emits an error if the option `--underscore' is
          in effect.

`.arch ARGUMENT'
     This is an assertion directive, giving an error if the specified
     ARGUMENT is not the same as the specified or default value for the
     `--march=ARCHITECTURE' option (*note march-option::).



File: as.info,  Node: D10V-Dependent,  Next: D30V-Dependent,  Prev: CRIS-Dependent,  Up: Machine Dependencies

8.6 D10V Dependent Features
===========================

* Menu:

* D10V-Opts::                   D10V Options
* D10V-Syntax::                 Syntax
* D10V-Float::                  Floating Point
* D10V-Opcodes::                Opcodes


File: as.info,  Node: D10V-Opts,  Next: D10V-Syntax,  Up: D10V-Dependent

8.6.1 D10V Options
------------------

The Mitsubishi D10V version of `as' has a few machine dependent options.

`-O'
     The D10V can often execute two sub-instructions in parallel. When
     this option is used, `as' will attempt to optimize its output by
     detecting when instructions can be executed in parallel.

`--nowarnswap'
     To optimize execution performance, `as' will sometimes swap the
     order of instructions. Normally this generates a warning. When
     this option is used, no warning will be generated when
     instructions are swapped.

`--gstabs-packing'

`--no-gstabs-packing'
     `as' packs adjacent short instructions into a single packed
     instruction. `--no-gstabs-packing' turns instruction packing off if
     `--gstabs' is specified as well; `--gstabs-packing' (the default)
     turns instruction packing on even when `--gstabs' is specified.


File: as.info,  Node: D10V-Syntax,  Next: D10V-Float,  Prev: D10V-Opts,  Up: D10V-Dependent

8.6.2 Syntax
------------

The D10V syntax is based on the syntax in Mitsubishi's D10V
architecture manual.  The differences are detailed below.

* Menu:

* D10V-Size::                 Size Modifiers
* D10V-Subs::                 Sub-Instructions
* D10V-Chars::                Special Characters
* D10V-Regs::                 Register Names
* D10V-Addressing::           Addressing Modes
* D10V-Word::                 @WORD Modifier


File: as.info,  Node: D10V-Size,  Next: D10V-Subs,  Up: D10V-Syntax

8.6.2.1 Size Modifiers
......................

The D10V version of `as' uses the instruction names in the D10V
Architecture Manual.  However, the names in the manual are sometimes
ambiguous.  There are instruction names that can assemble to a short or
long form opcode.  How does the assembler pick the correct form?  `as'
will always pick the smallest form if it can.  When dealing with a
symbol that is not defined yet when a line is being assembled, it will
always use the long form.  If you need to force the assembler to use
either the short or long form of the instruction, you can append either
`.s' (short) or `.l' (long) to it.  For example, if you are writing an
assembly program and you want to do a branch to a symbol that is
defined later in your program, you can write `bra.s   foo'.  Objdump
and GDB will always append `.s' or `.l' to instructions which have both
short and long forms.


File: as.info,  Node: D10V-Subs,  Next: D10V-Chars,  Prev: D10V-Size,  Up: D10V-Syntax

8.6.2.2 Sub-Instructions
........................

The D10V assembler takes as input a series of instructions, either
one-per-line, or in the special two-per-line format described in the
next section.  Some of these instructions will be short-form or
sub-instructions.  These sub-instructions can be packed into a single
instruction.  The assembler will do this automatically.  It will also
detect when it should not pack instructions.  For example, when a label
is defined, the next instruction will never be packaged with the
previous one.  Whenever a branch and link instruction is called, it
will not be packaged with the next instruction so the return address
will be valid.  Nops are automatically inserted when necessary.

   If you do not want the assembler automatically making these
decisions, you can control the packaging and execution type (parallel
or sequential) with the special execution symbols described in the next
section.


File: as.info,  Node: D10V-Chars,  Next: D10V-Regs,  Prev: D10V-Subs,  Up: D10V-Syntax

8.6.2.3 Special Characters
..........................

`;' and `#' are the line comment characters.  Sub-instructions may be
executed in order, in reverse-order, or in parallel.  Instructions
listed in the standard one-per-line format will be executed
sequentially.  To specify the executing order, use the following
symbols:
`->'
     Sequential with instruction on the left first.

`<-'
     Sequential with instruction on the right first.

`||'
     Parallel
   The D10V syntax allows either one instruction per line, one
instruction per line with the execution symbol, or two instructions per
line.  For example
`abs       a1      ->      abs     r0'
     Execute these sequentially.  The instruction on the right is in
     the right container and is executed second.

`abs       r0      <-      abs     a1'
     Execute these reverse-sequentially.  The instruction on the right
     is in the right container, and is executed first.

`ld2w    r2,@r8+         ||      mac     a0,r0,r7'
     Execute these in parallel.

`ld2w    r2,@r8+         ||'
`mac     a0,r0,r7'
     Two-line format. Execute these in parallel.

`ld2w    r2,@r8+'
`mac     a0,r0,r7'
     Two-line format. Execute these sequentially.  Assembler will put
     them in the proper containers.

`ld2w    r2,@r8+         ->'
`mac     a0,r0,r7'
     Two-line format. Execute these sequentially.  Same as above but
     second instruction will always go into right container.
   Since `$' has no special meaning, you may use it in symbol names.


File: as.info,  Node: D10V-Regs,  Next: D10V-Addressing,  Prev: D10V-Chars,  Up: D10V-Syntax

8.6.2.4 Register Names
......................

You can use the predefined symbols `r0' through `r15' to refer to the
D10V registers.  You can also use `sp' as an alias for `r15'.  The
accumulators are `a0' and `a1'.  There are special register-pair names
that may optionally be used in opcodes that require even-numbered
registers. Register names are not case sensitive.

   Register Pairs
`r0-r1'

`r2-r3'

`r4-r5'

`r6-r7'

`r8-r9'

`r10-r11'

`r12-r13'

`r14-r15'

   The D10V also has predefined symbols for these control registers and
status bits:
`psw'
     Processor Status Word

`bpsw'
     Backup Processor Status Word

`pc'
     Program Counter

`bpc'
     Backup Program Counter

`rpt_c'
     Repeat Count

`rpt_s'
     Repeat Start address

`rpt_e'
     Repeat End address

`mod_s'
     Modulo Start address

`mod_e'
     Modulo End address

`iba'
     Instruction Break Address

`f0'
     Flag 0

`f1'
     Flag 1

`c'
     Carry flag


File: as.info,  Node: D10V-Addressing,  Next: D10V-Word,  Prev: D10V-Regs,  Up: D10V-Syntax

8.6.2.5 Addressing Modes
........................

`as' understands the following addressing modes for the D10V.  `RN' in
the following refers to any of the numbered registers, but _not_ the
control registers.
`RN'
     Register direct

`@RN'
     Register indirect

`@RN+'
     Register indirect with post-increment

`@RN-'
     Register indirect with post-decrement

`@-SP'
     Register indirect with pre-decrement

`@(DISP, RN)'
     Register indirect with displacement

`ADDR'
     PC relative address (for branch or rep).

`#IMM'
     Immediate data (the `#' is optional and ignored)


File: as.info,  Node: D10V-Word,  Prev: D10V-Addressing,  Up: D10V-Syntax

8.6.2.6 @WORD Modifier
......................

Any symbol followed by `@word' will be replaced by the symbol's value
shifted right by 2.  This is used in situations such as loading a
register with the address of a function (or any other code fragment).
For example, if you want to load a register with the location of the
function `main' then jump to that function, you could do it as follows:
     ldi     r2, main@word
     jmp     r2


File: as.info,  Node: D10V-Float,  Next: D10V-Opcodes,  Prev: D10V-Syntax,  Up: D10V-Dependent

8.6.3 Floating Point
--------------------

The D10V has no hardware floating point, but the `.float' and `.double'
directives generates IEEE floating-point numbers for compatibility with
other development tools.


File: as.info,  Node: D10V-Opcodes,  Prev: D10V-Float,  Up: D10V-Dependent

8.6.4 Opcodes
-------------

For detailed information on the D10V machine instruction set, see `D10V
Architecture: A VLIW Microprocessor for Multimedia Applications'
(Mitsubishi Electric Corp.).  `as' implements all the standard D10V
opcodes.  The only changes are those described in the section on size
modifiers


File: as.info,  Node: D30V-Dependent,  Next: H8/300-Dependent,  Prev: D10V-Dependent,  Up: Machine Dependencies

8.7 D30V Dependent Features
===========================

* Menu:

* D30V-Opts::                   D30V Options
* D30V-Syntax::                 Syntax
* D30V-Float::                  Floating Point
* D30V-Opcodes::                Opcodes


File: as.info,  Node: D30V-Opts,  Next: D30V-Syntax,  Up: D30V-Dependent

8.7.1 D30V Options
------------------

The Mitsubishi D30V version of `as' has a few machine dependent options.

`-O'
     The D30V can often execute two sub-instructions in parallel. When
     this option is used, `as' will attempt to optimize its output by
     detecting when instructions can be executed in parallel.

`-n'
     When this option is used, `as' will issue a warning every time it
     adds a nop instruction.

`-N'
     When this option is used, `as' will issue a warning if it needs to
     insert a nop after a 32-bit multiply before a load or 16-bit
     multiply instruction.


File: as.info,  Node: D30V-Syntax,  Next: D30V-Float,  Prev: D30V-Opts,  Up: D30V-Dependent

8.7.2 Syntax
------------

The D30V syntax is based on the syntax in Mitsubishi's D30V
architecture manual.  The differences are detailed below.

* Menu:

* D30V-Size::                 Size Modifiers
* D30V-Subs::                 Sub-Instructions
* D30V-Chars::                Special Characters
* D30V-Guarded::              Guarded Execution
* D30V-Regs::                 Register Names
* D30V-Addressing::           Addressing Modes


File: as.info,  Node: D30V-Size,  Next: D30V-Subs,  Up: D30V-Syntax

8.7.2.1 Size Modifiers
......................

The D30V version of `as' uses the instruction names in the D30V
Architecture Manual.  However, the names in the manual are sometimes
ambiguous.  There are instruction names that can assemble to a short or
long form opcode.  How does the assembler pick the correct form?  `as'
will always pick the smallest form if it can.  When dealing with a
symbol that is not defined yet when a line is being assembled, it will
always use the long form.  If you need to force the assembler to use
either the short or long form of the instruction, you can append either
`.s' (short) or `.l' (long) to it.  For example, if you are writing an
assembly program and you want to do a branch to a symbol that is
defined later in your program, you can write `bra.s foo'.  Objdump and
GDB will always append `.s' or `.l' to instructions which have both
short and long forms.


File: as.info,  Node: D30V-Subs,  Next: D30V-Chars,  Prev: D30V-Size,  Up: D30V-Syntax

8.7.2.2 Sub-Instructions
........................

The D30V assembler takes as input a series of instructions, either
one-per-line, or in the special two-per-line format described in the
next section.  Some of these instructions will be short-form or
sub-instructions.  These sub-instructions can be packed into a single
instruction.  The assembler will do this automatically.  It will also
detect when it should not pack instructions.  For example, when a label
is defined, the next instruction will never be packaged with the
previous one.  Whenever a branch and link instruction is called, it
will not be packaged with the next instruction so the return address
will be valid.  Nops are automatically inserted when necessary.

   If you do not want the assembler automatically making these
decisions, you can control the packaging and execution type (parallel
or sequential) with the special execution symbols described in the next
section.


File: as.info,  Node: D30V-Chars,  Next: D30V-Guarded,  Prev: D30V-Subs,  Up: D30V-Syntax

8.7.2.3 Special Characters
..........................

`;' and `#' are the line comment characters.  Sub-instructions may be
executed in order, in reverse-order, or in parallel.  Instructions
listed in the standard one-per-line format will be executed
sequentially unless you use the `-O' option.

   To specify the executing order, use the following symbols:
`->'
     Sequential with instruction on the left first.

`<-'
     Sequential with instruction on the right first.

`||'
     Parallel

   The D30V syntax allows either one instruction per line, one
instruction per line with the execution symbol, or two instructions per
line.  For example
`abs r2,r3 -> abs r4,r5'
     Execute these sequentially.  The instruction on the right is in
     the right container and is executed second.

`abs r2,r3 <- abs r4,r5'
     Execute these reverse-sequentially.  The instruction on the right
     is in the right container, and is executed first.

`abs r2,r3 || abs r4,r5'
     Execute these in parallel.

`ldw r2,@(r3,r4) ||'
`mulx r6,r8,r9'
     Two-line format. Execute these in parallel.

`mulx a0,r8,r9'
`stw r2,@(r3,r4)'
     Two-line format. Execute these sequentially unless `-O' option is
     used.  If the `-O' option is used, the assembler will determine if
     the instructions could be done in parallel (the above two
     instructions can be done in parallel), and if so, emit them as
     parallel instructions.  The assembler will put them in the proper
     containers.  In the above example, the assembler will put the
     `stw' instruction in left container and the `mulx' instruction in
     the right container.

`stw r2,@(r3,r4) ->'
`mulx a0,r8,r9'
     Two-line format.  Execute the `stw' instruction followed by the
     `mulx' instruction sequentially.  The first instruction goes in the
     left container and the second instruction goes into right
     container.  The assembler will give an error if the machine
     ordering constraints are violated.

`stw r2,@(r3,r4) <-'
`mulx a0,r8,r9'
     Same as previous example, except that the `mulx' instruction is
     executed before the `stw' instruction.

   Since `$' has no special meaning, you may use it in symbol names.


File: as.info,  Node: D30V-Guarded,  Next: D30V-Regs,  Prev: D30V-Chars,  Up: D30V-Syntax

8.7.2.4 Guarded Execution
.........................

`as' supports the full range of guarded execution directives for each
instruction.  Just append the directive after the instruction proper.
The directives are:

`/tx'
     Execute the instruction if flag f0 is true.

`/fx'
     Execute the instruction if flag f0 is false.

`/xt'
     Execute the instruction if flag f1 is true.

`/xf'
     Execute the instruction if flag f1 is false.

`/tt'
     Execute the instruction if both flags f0 and f1 are true.

`/tf'
     Execute the instruction if flag f0 is true and flag f1 is false.


File: as.info,  Node: D30V-Regs,  Next: D30V-Addressing,  Prev: D30V-Guarded,  Up: D30V-Syntax

8.7.2.5 Register Names
......................

You can use the predefined symbols `r0' through `r63' to refer to the
D30V registers.  You can also use `sp' as an alias for `r63' and `link'
as an alias for `r62'.  The accumulators are `a0' and `a1'.

   The D30V also has predefined symbols for these control registers and
status bits:
`psw'
     Processor Status Word

`bpsw'
     Backup Processor Status Word

`pc'
     Program Counter

`bpc'
     Backup Program Counter

`rpt_c'
     Repeat Count

`rpt_s'
     Repeat Start address

`rpt_e'
     Repeat End address

`mod_s'
     Modulo Start address

`mod_e'
     Modulo End address

`iba'
     Instruction Break Address

`f0'
     Flag 0

`f1'
     Flag 1

`f2'
     Flag 2

`f3'
     Flag 3

`f4'
     Flag 4

`f5'
     Flag 5

`f6'
     Flag 6

`f7'
     Flag 7

`s'
     Same as flag 4 (saturation flag)

`v'
     Same as flag 5 (overflow flag)

`va'
     Same as flag 6 (sticky overflow flag)

`c'
     Same as flag 7 (carry/borrow flag)

`b'
     Same as flag 7 (carry/borrow flag)


File: as.info,  Node: D30V-Addressing,  Prev: D30V-Regs,  Up: D30V-Syntax

8.7.2.6 Addressing Modes
........................

`as' understands the following addressing modes for the D30V.  `RN' in
the following refers to any of the numbered registers, but _not_ the
control registers.
`RN'
     Register direct

`@RN'
     Register indirect

`@RN+'
     Register indirect with post-increment

`@RN-'
     Register indirect with post-decrement

`@-SP'
     Register indirect with pre-decrement

`@(DISP, RN)'
     Register indirect with displacement

`ADDR'
     PC relative address (for branch or rep).

`#IMM'
     Immediate data (the `#' is optional and ignored)


File: as.info,  Node: D30V-Float,  Next: D30V-Opcodes,  Prev: D30V-Syntax,  Up: D30V-Dependent

8.7.3 Floating Point
--------------------

The D30V has no hardware floating point, but the `.float' and `.double'
directives generates IEEE floating-point numbers for compatibility with
other development tools.


File: as.info,  Node: D30V-Opcodes,  Prev: D30V-Float,  Up: D30V-Dependent

8.7.4 Opcodes
-------------

For detailed information on the D30V machine instruction set, see `D30V
Architecture: A VLIW Microprocessor for Multimedia Applications'
(Mitsubishi Electric Corp.).  `as' implements all the standard D30V
opcodes.  The only changes are those described in the section on size
modifiers


File: as.info,  Node: H8/300-Dependent,  Next: HPPA-Dependent,  Prev: D30V-Dependent,  Up: Machine Dependencies

8.8 H8/300 Dependent Features
=============================

* Menu:

* H8/300 Options::              Options
* H8/300 Syntax::               Syntax
* H8/300 Floating Point::       Floating Point
* H8/300 Directives::           H8/300 Machine Directives
* H8/300 Opcodes::              Opcodes


File: as.info,  Node: H8/300 Options,  Next: H8/300 Syntax,  Up: H8/300-Dependent

8.8.1 Options
-------------

`as' has no additional command-line options for the Renesas (formerly
Hitachi) H8/300 family.


File: as.info,  Node: H8/300 Syntax,  Next: H8/300 Floating Point,  Prev: H8/300 Options,  Up: H8/300-Dependent

8.8.2 Syntax
------------

* Menu:

* H8/300-Chars::                Special Characters
* H8/300-Regs::                 Register Names
* H8/300-Addressing::           Addressing Modes


File: as.info,  Node: H8/300-Chars,  Next: H8/300-Regs,  Up: H8/300 Syntax

8.8.2.1 Special Characters
..........................

`;' is the line comment character.

   `$' can be used instead of a newline to separate statements.
Therefore _you may not use `$' in symbol names_ on the H8/300.


File: as.info,  Node: H8/300-Regs,  Next: H8/300-Addressing,  Prev: H8/300-Chars,  Up: H8/300 Syntax

8.8.2.2 Register Names
......................

You can use predefined symbols of the form `rNh' and `rNl' to refer to
the H8/300 registers as sixteen 8-bit general-purpose registers.  N is
a digit from `0' to `7'); for instance, both `r0h' and `r7l' are valid
register names.

   You can also use the eight predefined symbols `rN' to refer to the
H8/300 registers as 16-bit registers (you must use this form for
addressing).

   On the H8/300H, you can also use the eight predefined symbols `erN'
(`er0' ... `er7') to refer to the 32-bit general purpose registers.

   The two control registers are called `pc' (program counter; a 16-bit
register, except on the H8/300H where it is 24 bits) and `ccr'
(condition code register; an 8-bit register).  `r7' is used as the
stack pointer, and can also be called `sp'.


File: as.info,  Node: H8/300-Addressing,  Prev: H8/300-Regs,  Up: H8/300 Syntax

8.8.2.3 Addressing Modes
........................

as understands the following addressing modes for the H8/300:
`rN'
     Register direct

`@rN'
     Register indirect

`@(D, rN)'
`@(D:16, rN)'
`@(D:24, rN)'
     Register indirect: 16-bit or 24-bit displacement D from register
     N.  (24-bit displacements are only meaningful on the H8/300H.)

`@rN+'
     Register indirect with post-increment

`@-rN'
     Register indirect with pre-decrement

``@'AA'
``@'AA:8'
``@'AA:16'
``@'AA:24'
     Absolute address `aa'.  (The address size `:24' only makes sense
     on the H8/300H.)

`#XX'
`#XX:8'
`#XX:16'
`#XX:32'
     Immediate data XX.  You may specify the `:8', `:16', or `:32' for
     clarity, if you wish; but `as' neither requires this nor uses
     it--the data size required is taken from context.

``@'`@'AA'
``@'`@'AA:8'
     Memory indirect.  You may specify the `:8' for clarity, if you
     wish; but `as' neither requires this nor uses it.


File: as.info,  Node: H8/300 Floating Point,  Next: H8/300 Directives,  Prev: H8/300 Syntax,  Up: H8/300-Dependent

8.8.3 Floating Point
--------------------

The H8/300 family has no hardware floating point, but the `.float'
directive generates IEEE floating-point numbers for compatibility with
other development tools.


File: as.info,  Node: H8/300 Directives,  Next: H8/300 Opcodes,  Prev: H8/300 Floating Point,  Up: H8/300-Dependent

8.8.4 H8/300 Machine Directives
-------------------------------

`as' has the following machine-dependent directives for the H8/300:

`.h8300h'
     Recognize and emit additional instructions for the H8/300H
     variant, and also make `.int' emit 32-bit numbers rather than the
     usual (16-bit) for the H8/300 family.

`.h8300s'
     Recognize and emit additional instructions for the H8S variant, and
     also make `.int' emit 32-bit numbers rather than the usual (16-bit)
     for the H8/300 family.

`.h8300hn'
     Recognize and emit additional instructions for the H8/300H variant
     in normal mode, and also make `.int' emit 32-bit numbers rather
     than the usual (16-bit) for the H8/300 family.

`.h8300sn'
     Recognize and emit additional instructions for the H8S variant in
     normal mode, and also make `.int' emit 32-bit numbers rather than
     the usual (16-bit) for the H8/300 family.

   On the H8/300 family (including the H8/300H) `.word' directives
generate 16-bit numbers.


File: as.info,  Node: H8/300 Opcodes,  Prev: H8/300 Directives,  Up: H8/300-Dependent

8.8.5 Opcodes
-------------

For detailed information on the H8/300 machine instruction set, see
`H8/300 Series Programming Manual'.  For information specific to the
H8/300H, see `H8/300H Series Programming Manual' (Renesas).

   `as' implements all the standard H8/300 opcodes.  No additional
pseudo-instructions are needed on this family.

   The following table summarizes the H8/300 opcodes, and their
arguments.  Entries marked `*' are opcodes used only on the H8/300H.

              Legend:
                 Rs   source register
                 Rd   destination register
                 abs  absolute address
                 imm  immediate data
              disp:N  N-bit displacement from a register
             pcrel:N  N-bit displacement relative to program counter

        add.b #imm,rd              *  andc #imm,ccr
        add.b rs,rd                   band #imm,rd
        add.w rs,rd                   band #imm,@rd
     *  add.w #imm,rd                 band #imm,@abs:8
     *  add.l rs,rd                   bra  pcrel:8
     *  add.l #imm,rd              *  bra  pcrel:16
        adds #imm,rd                  bt   pcrel:8
        addx #imm,rd               *  bt   pcrel:16
        addx rs,rd                    brn  pcrel:8
        and.b #imm,rd              *  brn  pcrel:16
        and.b rs,rd                   bf   pcrel:8
     *  and.w rs,rd                *  bf   pcrel:16
     *  and.w #imm,rd                 bhi  pcrel:8
     *  and.l #imm,rd              *  bhi  pcrel:16
     *  and.l rs,rd                   bls  pcrel:8

     *  bls  pcrel:16                 bld  #imm,rd
        bcc  pcrel:8                  bld  #imm,@rd
     *  bcc  pcrel:16                 bld  #imm,@abs:8
        bhs  pcrel:8                  bnot #imm,rd
     *  bhs  pcrel:16                 bnot #imm,@rd
        bcs  pcrel:8                  bnot #imm,@abs:8
     *  bcs  pcrel:16                 bnot rs,rd
        blo  pcrel:8                  bnot rs,@rd
     *  blo  pcrel:16                 bnot rs,@abs:8
        bne  pcrel:8                  bor  #imm,rd
     *  bne  pcrel:16                 bor  #imm,@rd
        beq  pcrel:8                  bor  #imm,@abs:8
     *  beq  pcrel:16                 bset #imm,rd
        bvc  pcrel:8                  bset #imm,@rd
     *  bvc  pcrel:16                 bset #imm,@abs:8
        bvs  pcrel:8                  bset rs,rd
     *  bvs  pcrel:16                 bset rs,@rd
        bpl  pcrel:8                  bset rs,@abs:8
     *  bpl  pcrel:16                 bsr  pcrel:8
        bmi  pcrel:8                  bsr  pcrel:16
     *  bmi  pcrel:16                 bst  #imm,rd
        bge  pcrel:8                  bst  #imm,@rd
     *  bge  pcrel:16                 bst  #imm,@abs:8
        blt  pcrel:8                  btst #imm,rd
     *  blt  pcrel:16                 btst #imm,@rd
        bgt  pcrel:8                  btst #imm,@abs:8
     *  bgt  pcrel:16                 btst rs,rd
        ble  pcrel:8                  btst rs,@rd
     *  ble  pcrel:16                 btst rs,@abs:8
        bclr #imm,rd                  bxor #imm,rd
        bclr #imm,@rd                 bxor #imm,@rd
        bclr #imm,@abs:8              bxor #imm,@abs:8
        bclr rs,rd                    cmp.b #imm,rd
        bclr rs,@rd                   cmp.b rs,rd
        bclr rs,@abs:8                cmp.w rs,rd
        biand #imm,rd                 cmp.w rs,rd
        biand #imm,@rd             *  cmp.w #imm,rd
        biand #imm,@abs:8          *  cmp.l #imm,rd
        bild #imm,rd               *  cmp.l rs,rd
        bild #imm,@rd                 daa  rs
        bild #imm,@abs:8              das  rs
        bior #imm,rd                  dec.b rs
        bior #imm,@rd              *  dec.w #imm,rd
        bior #imm,@abs:8           *  dec.l #imm,rd
        bist #imm,rd                  divxu.b rs,rd
        bist #imm,@rd              *  divxu.w rs,rd
        bist #imm,@abs:8           *  divxs.b rs,rd
        bixor #imm,rd              *  divxs.w rs,rd
        bixor #imm,@rd                eepmov
        bixor #imm,@abs:8          *  eepmovw

     *  exts.w rd                     mov.w rs,@abs:16
     *  exts.l rd                  *  mov.l #imm,rd
     *  extu.w rd                  *  mov.l rs,rd
     *  extu.l rd                  *  mov.l @rs,rd
        inc  rs                    *  mov.l @(disp:16,rs),rd
     *  inc.w #imm,rd              *  mov.l @(disp:24,rs),rd
     *  inc.l #imm,rd              *  mov.l @rs+,rd
        jmp  @rs                   *  mov.l @abs:16,rd
        jmp  abs                   *  mov.l @abs:24,rd
        jmp  @@abs:8               *  mov.l rs,@rd
        jsr  @rs                   *  mov.l rs,@(disp:16,rd)
        jsr  abs                   *  mov.l rs,@(disp:24,rd)
        jsr  @@abs:8               *  mov.l rs,@-rd
        ldc  #imm,ccr              *  mov.l rs,@abs:16
        ldc  rs,ccr                *  mov.l rs,@abs:24
     *  ldc  @abs:16,ccr              movfpe @abs:16,rd
     *  ldc  @abs:24,ccr              movtpe rs,@abs:16
     *  ldc  @(disp:16,rs),ccr        mulxu.b rs,rd
     *  ldc  @(disp:24,rs),ccr     *  mulxu.w rs,rd
     *  ldc  @rs+,ccr              *  mulxs.b rs,rd
     *  ldc  @rs,ccr               *  mulxs.w rs,rd
     *  mov.b @(disp:24,rs),rd        neg.b rs
     *  mov.b rs,@(disp:24,rd)     *  neg.w rs
        mov.b @abs:16,rd           *  neg.l rs
        mov.b rs,rd                   nop
        mov.b @abs:8,rd               not.b rs
        mov.b rs,@abs:8            *  not.w rs
        mov.b rs,rd                *  not.l rs
        mov.b #imm,rd                 or.b #imm,rd
        mov.b @rs,rd                  or.b rs,rd
        mov.b @(disp:16,rs),rd     *  or.w #imm,rd
        mov.b @rs+,rd              *  or.w rs,rd
        mov.b @abs:8,rd            *  or.l #imm,rd
        mov.b rs,@rd               *  or.l rs,rd
        mov.b rs,@(disp:16,rd)        orc  #imm,ccr
        mov.b rs,@-rd                 pop.w rs
        mov.b rs,@abs:8            *  pop.l rs
        mov.w rs,@rd                  push.w rs
     *  mov.w @(disp:24,rs),rd     *  push.l rs
     *  mov.w rs,@(disp:24,rd)        rotl.b rs
     *  mov.w @abs:24,rd           *  rotl.w rs
     *  mov.w rs,@abs:24           *  rotl.l rs
        mov.w rs,rd                   rotr.b rs
        mov.w #imm,rd              *  rotr.w rs
        mov.w @rs,rd               *  rotr.l rs
        mov.w @(disp:16,rs),rd        rotxl.b rs
        mov.w @rs+,rd              *  rotxl.w rs
        mov.w @abs:16,rd           *  rotxl.l rs
        mov.w rs,@(disp:16,rd)        rotxr.b rs
        mov.w rs,@-rd              *  rotxr.w rs

     *  rotxr.l rs                 *  stc  ccr,@(disp:24,rd)
        bpt                        *  stc  ccr,@-rd
        rte                        *  stc  ccr,@abs:16
        rts                        *  stc  ccr,@abs:24
        shal.b rs                     sub.b rs,rd
     *  shal.w rs                     sub.w rs,rd
     *  shal.l rs                  *  sub.w #imm,rd
        shar.b rs                  *  sub.l rs,rd
     *  shar.w rs                  *  sub.l #imm,rd
     *  shar.l rs                     subs #imm,rd
        shll.b rs                     subx #imm,rd
     *  shll.w rs                     subx rs,rd
     *  shll.l rs                  *  trapa #imm
        shlr.b rs                     xor  #imm,rd
     *  shlr.w rs                     xor  rs,rd
     *  shlr.l rs                  *  xor.w #imm,rd
        sleep                      *  xor.w rs,rd
        stc  ccr,rd                *  xor.l #imm,rd
     *  stc  ccr,@rs               *  xor.l rs,rd
     *  stc  ccr,@(disp:16,rd)        xorc #imm,ccr

   Four H8/300 instructions (`add', `cmp', `mov', `sub') are defined
with variants using the suffixes `.b', `.w', and `.l' to specify the
size of a memory operand.  `as' supports these suffixes, but does not
require them; since one of the operands is always a register, `as' can
deduce the correct size.

   For example, since `r0' refers to a 16-bit register,
     mov    r0,@foo
is equivalent to
     mov.w  r0,@foo

   If you use the size suffixes, `as' issues a warning when the suffix
and the register size do not match.


File: as.info,  Node: HPPA-Dependent,  Next: ESA/390-Dependent,  Prev: H8/300-Dependent,  Up: Machine Dependencies

8.9 HPPA Dependent Features
===========================

* Menu:

* HPPA Notes::                Notes
* HPPA Options::              Options
* HPPA Syntax::               Syntax
* HPPA Floating Point::       Floating Point
* HPPA Directives::           HPPA Machine Directives
* HPPA Opcodes::              Opcodes


File: as.info,  Node: HPPA Notes,  Next: HPPA Options,  Up: HPPA-Dependent

8.9.1 Notes
-----------

As a back end for GNU CC `as' has been throughly tested and should work
extremely well.  We have tested it only minimally on hand written
assembly code and no one has tested it much on the assembly output from
the HP compilers.

   The format of the debugging sections has changed since the original
`as' port (version 1.3X) was released; therefore, you must rebuild all
HPPA objects and libraries with the new assembler so that you can debug
the final executable.

   The HPPA `as' port generates a small subset of the relocations
available in the SOM and ELF object file formats.  Additional relocation
support will be added as it becomes necessary.


File: as.info,  Node: HPPA Options,  Next: HPPA Syntax,  Prev: HPPA Notes,  Up: HPPA-Dependent

8.9.2 Options
-------------

`as' has no machine-dependent command-line options for the HPPA.


File: as.info,  Node: HPPA Syntax,  Next: HPPA Floating Point,  Prev: HPPA Options,  Up: HPPA-Dependent

8.9.3 Syntax
------------

The assembler syntax closely follows the HPPA instruction set reference
manual; assembler directives and general syntax closely follow the HPPA
assembly language reference manual, with a few noteworthy differences.

   First, a colon may immediately follow a label definition.  This is
simply for compatibility with how most assembly language programmers
write code.

   Some obscure expression parsing problems may affect hand written
code which uses the `spop' instructions, or code which makes significant
use of the `!' line separator.

   `as' is much less forgiving about missing arguments and other
similar oversights than the HP assembler.  `as' notifies you of missing
arguments as syntax errors; this is regarded as a feature, not a bug.

   Finally, `as' allows you to use an external symbol without
explicitly importing the symbol.  _Warning:_ in the future this will be
an error for HPPA targets.

   Special characters for HPPA targets include:

   `;' is the line comment character.

   `!' can be used instead of a newline to separate statements.

   Since `$' has no special meaning, you may use it in symbol names.


File: as.info,  Node: HPPA Floating Point,  Next: HPPA Directives,  Prev: HPPA Syntax,  Up: HPPA-Dependent

8.9.4 Floating Point
--------------------

The HPPA family uses IEEE floating-point numbers.


File: as.info,  Node: HPPA Directives,  Next: HPPA Opcodes,  Prev: HPPA Floating Point,  Up: HPPA-Dependent

8.9.5 HPPA Assembler Directives
-------------------------------

`as' for the HPPA supports many additional directives for compatibility
with the native assembler.  This section describes them only briefly.
For detailed information on HPPA-specific assembler directives, see
`HP9000 Series 800 Assembly Language Reference Manual' (HP 92432-90001).

   `as' does _not_ support the following assembler directives described
in the HP manual:

     .endm           .liston
     .enter          .locct
     .leave          .macro
     .listoff

   Beyond those implemented for compatibility, `as' supports one
additional assembler directive for the HPPA: `.param'.  It conveys
register argument locations for static functions.  Its syntax closely
follows the `.export' directive.

   These are the additional directives in `as' for the HPPA:

`.block N'
`.blockz N'
     Reserve N bytes of storage, and initialize them to zero.

`.call'
     Mark the beginning of a procedure call.  Only the special case
     with _no arguments_ is allowed.

`.callinfo [ PARAM=VALUE, ... ]  [ FLAG, ... ]'
     Specify a number of parameters and flags that define the
     environment for a procedure.

     PARAM may be any of `frame' (frame size), `entry_gr' (end of
     general register range), `entry_fr' (end of float register range),
     `entry_sr' (end of space register range).

     The values for FLAG are `calls' or `caller' (proc has
     subroutines), `no_calls' (proc does not call subroutines),
     `save_rp' (preserve return pointer), `save_sp' (proc preserves
     stack pointer), `no_unwind' (do not unwind this proc), `hpux_int'
     (proc is interrupt routine).

`.code'
     Assemble into the standard section called `$TEXT$', subsection
     `$CODE$'.

`.copyright "STRING"'
     In the SOM object format, insert STRING into the object code,
     marked as a copyright string.

`.copyright "STRING"'
     In the ELF object format, insert STRING into the object code,
     marked as a version string.

`.enter'
     Not yet supported; the assembler rejects programs containing this
     directive.

`.entry'
     Mark the beginning of a procedure.

`.exit'
     Mark the end of a procedure.

`.export NAME [ ,TYP ]  [ ,PARAM=R ]'
     Make a procedure NAME available to callers.  TYP, if present, must
     be one of `absolute', `code' (ELF only, not SOM), `data', `entry',
     `data', `entry', `millicode', `plabel', `pri_prog', or `sec_prog'.

     PARAM, if present, provides either relocation information for the
     procedure arguments and result, or a privilege level.  PARAM may be
     `argwN' (where N ranges from `0' to `3', and indicates one of four
     one-word arguments); `rtnval' (the procedure's result); or
     `priv_lev' (privilege level).  For arguments or the result, R
     specifies how to relocate, and must be one of `no' (not
     relocatable), `gr' (argument is in general register), `fr' (in
     floating point register), or `fu' (upper half of float register).
     For `priv_lev', R is an integer.

`.half N'
     Define a two-byte integer constant N; synonym for the portable
     `as' directive `.short'.

`.import NAME [ ,TYP ]'
     Converse of `.export'; make a procedure available to call.  The
     arguments use the same conventions as the first two arguments for
     `.export'.

`.label NAME'
     Define NAME as a label for the current assembly location.

`.leave'
     Not yet supported; the assembler rejects programs containing this
     directive.

`.origin LC'
     Advance location counter to LC. Synonym for the `as' portable
     directive `.org'.

`.param NAME [ ,TYP ]  [ ,PARAM=R ]'
     Similar to `.export', but used for static procedures.

`.proc'
     Use preceding the first statement of a procedure.

`.procend'
     Use following the last statement of a procedure.

`LABEL .reg EXPR'
     Synonym for `.equ'; define LABEL with the absolute expression EXPR
     as its value.

`.space SECNAME [ ,PARAMS ]'
     Switch to section SECNAME, creating a new section by that name if
     necessary.  You may only use PARAMS when creating a new section,
     not when switching to an existing one.  SECNAME may identify a
     section by number rather than by name.

     If specified, the list PARAMS declares attributes of the section,
     identified by keywords.  The keywords recognized are `spnum=EXP'
     (identify this section by the number EXP, an absolute expression),
     `sort=EXP' (order sections according to this sort key when linking;
     EXP is an absolute expression), `unloadable' (section contains no
     loadable data), `notdefined' (this section defined elsewhere), and
     `private' (data in this section not available to other programs).

`.spnum SECNAM'
     Allocate four bytes of storage, and initialize them with the
     section number of the section named SECNAM.  (You can define the
     section number with the HPPA `.space' directive.)

`.string "STR"'
     Copy the characters in the string STR to the object file.  *Note
     Strings: Strings, for information on escape sequences you can use
     in `as' strings.

     _Warning!_ The HPPA version of `.string' differs from the usual
     `as' definition: it does _not_ write a zero byte after copying STR.

`.stringz "STR"'
     Like `.string', but appends a zero byte after copying STR to object
     file.

`.subspa NAME [ ,PARAMS ]'
`.nsubspa NAME [ ,PARAMS ]'
     Similar to `.space', but selects a subsection NAME within the
     current section.  You may only specify PARAMS when you create a
     subsection (in the first instance of `.subspa' for this NAME).

     If specified, the list PARAMS declares attributes of the
     subsection, identified by keywords.  The keywords recognized are
     `quad=EXPR' ("quadrant" for this subsection), `align=EXPR'
     (alignment for beginning of this subsection; a power of two),
     `access=EXPR' (value for "access rights" field), `sort=EXPR'
     (sorting order for this subspace in link), `code_only' (subsection
     contains only code), `unloadable' (subsection cannot be loaded
     into memory), `comdat' (subsection is comdat), `common'
     (subsection is common block), `dup_comm' (subsection may have
     duplicate names), or `zero' (subsection is all zeros, do not write
     in object file).

     `.nsubspa' always creates a new subspace with the given name, even
     if one with the same name already exists.

     `comdat', `common' and `dup_comm' can be used to implement various
     flavors of one-only support when using the SOM linker.  The SOM
     linker only supports specific combinations of these flags.  The
     details are not documented.  A brief description is provided here.

     `comdat' provides a form of linkonce support.  It is useful for
     both code and data subspaces.  A `comdat' subspace has a key symbol
     marked by the `is_comdat' flag or `ST_COMDAT'.  Only the first
     subspace for any given key is selected.  The key symbol becomes
     universal in shared links.  This is similar to the behavior of
     `secondary_def' symbols.

     `common' provides Fortran named common support.  It is only useful
     for data subspaces.  Symbols with the flag `is_common' retain this
     flag in shared links.  Referencing a `is_common' symbol in a shared
     library from outside the library doesn't work.  Thus, `is_common'
     symbols must be output whenever they are needed.

     `common' and `dup_comm' together provide Cobol common support.
     The subspaces in this case must all be the same length.
     Otherwise, this support is similar to the Fortran common support.

     `dup_comm' by itself provides a type of one-only support for code.
     Only the first `dup_comm' subspace is selected.  There is a rather
     complex algorithm to compare subspaces.  Code symbols marked with
     the `dup_common' flag are hidden.  This support was intended for
     "C++ duplicate inlines".

     A simplified technique is used to mark the flags of symbols based
     on the flags of their subspace.  A symbol with the scope
     SS_UNIVERSAL and type ST_ENTRY, ST_CODE or ST_DATA is marked with
     the corresponding settings of `comdat', `common' and `dup_comm'
     from the subspace, respectively.  This avoids having to introduce
     additional directives to mark these symbols.  The HP assembler
     sets `is_common' from `common'.  However, it doesn't set the
     `dup_common' from `dup_comm'.  It doesn't have `comdat' support.

`.version "STR"'
     Write STR as version identifier in object code.


File: as.info,  Node: HPPA Opcodes,  Prev: HPPA Directives,  Up: HPPA-Dependent

8.9.6 Opcodes
-------------

For detailed information on the HPPA machine instruction set, see
`PA-RISC Architecture and Instruction Set Reference Manual' (HP
09740-90039).


File: as.info,  Node: ESA/390-Dependent,  Next: i386-Dependent,  Prev: HPPA-Dependent,  Up: Machine Dependencies

8.10 ESA/390 Dependent Features
===============================

* Menu:

* ESA/390 Notes::                Notes
* ESA/390 Options::              Options
* ESA/390 Syntax::               Syntax
* ESA/390 Floating Point::       Floating Point
* ESA/390 Directives::           ESA/390 Machine Directives
* ESA/390 Opcodes::              Opcodes


File: as.info,  Node: ESA/390 Notes,  Next: ESA/390 Options,  Up: ESA/390-Dependent

8.10.1 Notes
------------

The ESA/390 `as' port is currently intended to be a back-end for the
GNU CC compiler.  It is not HLASM compatible, although it does support
a subset of some of the HLASM directives.  The only supported binary
file format is ELF; none of the usual MVS/VM/OE/USS object file
formats, such as ESD or XSD, are supported.

   When used with the GNU CC compiler, the ESA/390 `as' will produce
correct, fully relocated, functional binaries, and has been used to
compile and execute large projects.  However, many aspects should still
be considered experimental; these include shared library support,
dynamically loadable objects, and any relocation other than the 31-bit
relocation.


File: as.info,  Node: ESA/390 Options,  Next: ESA/390 Syntax,  Prev: ESA/390 Notes,  Up: ESA/390-Dependent

8.10.2 Options
--------------

`as' has no machine-dependent command-line options for the ESA/390.


File: as.info,  Node: ESA/390 Syntax,  Next: ESA/390 Floating Point,  Prev: ESA/390 Options,  Up: ESA/390-Dependent

8.10.3 Syntax
-------------

The opcode/operand syntax follows the ESA/390 Principles of Operation
manual; assembler directives and general syntax are loosely based on the
prevailing AT&T/SVR4/ELF/Solaris style notation.  HLASM-style directives
are _not_ supported for the most part, with the exception of those
described herein.

   A leading dot in front of directives is optional, and the case of
directives is ignored; thus for example, .using and USING have the same
effect.

   A colon may immediately follow a label definition.  This is simply
for compatibility with how most assembly language programmers write
code.

   `#' is the line comment character.

   `;' can be used instead of a newline to separate statements.

   Since `$' has no special meaning, you may use it in symbol names.

   Registers can be given the symbolic names r0..r15, fp0, fp2, fp4,
fp6.  By using thesse symbolic names, `as' can detect simple syntax
errors. The name rarg or r.arg is a synonym for r11, rtca or r.tca for
r12, sp, r.sp, dsa r.dsa for r13, lr or r.lr for r14, rbase or r.base
for r3 and rpgt or r.pgt for r4.

   `*' is the current location counter.  Unlike `.' it is always
relative to the last USING directive.  Note that this means that
expressions cannot use multiplication, as any occurrence of `*' will be
interpreted as a location counter.

   All labels are relative to the last USING.  Thus, branches to a label
always imply the use of base+displacement.

   Many of the usual forms of address constants / address literals are
supported.  Thus,
     	.using	*,r3
     	L	r15,=A(some_routine)
     	LM	r6,r7,=V(some_longlong_extern)
     	A	r1,=F'12'
     	AH	r0,=H'42'
     	ME	r6,=E'3.1416'
     	MD	r6,=D'3.14159265358979'
     	O	r6,=XL4'cacad0d0'
     	.ltorg
   should all behave as expected: that is, an entry in the literal pool
will be created (or reused if it already exists), and the instruction
operands will be the displacement into the literal pool using the
current base register (as last declared with the `.using' directive).


File: as.info,  Node: ESA/390 Floating Point,  Next: ESA/390 Directives,  Prev: ESA/390 Syntax,  Up: ESA/390-Dependent

8.10.4 Floating Point
---------------------

The assembler generates only IEEE floating-point numbers.  The older
floating point formats are not supported.


File: as.info,  Node: ESA/390 Directives,  Next: ESA/390 Opcodes,  Prev: ESA/390 Floating Point,  Up: ESA/390-Dependent

8.10.5 ESA/390 Assembler Directives
-----------------------------------

`as' for the ESA/390 supports all of the standard ELF/SVR4 assembler
directives that are documented in the main part of this documentation.
Several additional directives are supported in order to implement the
ESA/390 addressing model.  The most important of these are `.using' and
`.ltorg'

   These are the additional directives in `as' for the ESA/390:

`.dc'
     A small subset of the usual DC directive is supported.

`.drop REGNO'
     Stop using REGNO as the base register.  The REGNO must have been
     previously declared with a `.using' directive in the same section
     as the current section.

`.ebcdic STRING'
     Emit the EBCDIC equivalent of the indicated string.  The emitted
     string will be null terminated.  Note that the directives
     `.string' etc. emit ascii strings by default.

`EQU'
     The standard HLASM-style EQU directive is not supported; however,
     the standard `as' directive .equ can be used to the same effect.

`.ltorg'
     Dump the literal pool accumulated so far; begin a new literal pool.
     The literal pool will be written in the current section; in order
     to generate correct assembly, a `.using' must have been previously
     specified in the same section.

`.using EXPR,REGNO'
     Use REGNO as the base register for all subsequent RX, RS, and SS
     form instructions. The EXPR will be evaluated to obtain the base
     address; usually, EXPR will merely be `*'.

     This assembler allows two `.using' directives to be simultaneously
     outstanding, one in the `.text' section, and one in another section
     (typically, the `.data' section).  This feature allows dynamically
     loaded objects to be implemented in a relatively straightforward
     way.  A `.using' directive must always be specified in the `.text'
     section; this will specify the base register that will be used for
     branches in the `.text' section.  A second `.using' may be
     specified in another section; this will specify the base register
     that is used for non-label address literals.  When a second
     `.using' is specified, then the subsequent `.ltorg' must be put in
     the same section; otherwise an error will result.

     Thus, for example, the following code uses `r3' to address branch
     targets and `r4' to address the literal pool, which has been
     written to the `.data' section.  The is, the constants
     `=A(some_routine)', `=H'42'' and `=E'3.1416'' will all appear in
     the `.data' section.

          .data
          	.using  LITPOOL,r4
          .text
          	BASR	r3,0
          	.using	*,r3
                  B       START
          	.long	LITPOOL
          START:
          	L	r4,4(,r3)
          	L	r15,=A(some_routine)
          	LTR	r15,r15
          	BNE	LABEL
          	AH	r0,=H'42'
          LABEL:
          	ME	r6,=E'3.1416'
          .data
          LITPOOL:
          	.ltorg

     Note that this dual-`.using' directive semantics extends and is
     not compatible with HLASM semantics.  Note that this assembler
     directive does not support the full range of HLASM semantics.



File: as.info,  Node: ESA/390 Opcodes,  Prev: ESA/390 Directives,  Up: ESA/390-Dependent

8.10.6 Opcodes
--------------

For detailed information on the ESA/390 machine instruction set, see
`ESA/390 Principles of Operation' (IBM Publication Number DZ9AR004).


File: as.info,  Node: i386-Dependent,  Next: i860-Dependent,  Prev: ESA/390-Dependent,  Up: Machine Dependencies

8.11 80386 Dependent Features
=============================

   The i386 version `as' supports both the original Intel 386
architecture in both 16 and 32-bit mode as well as AMD x86-64
architecture extending the Intel architecture to 64-bits.

* Menu:

* i386-Options::                Options
* i386-Syntax::                 AT&T Syntax versus Intel Syntax
* i386-Mnemonics::              Instruction Naming
* i386-Regs::                   Register Naming
* i386-Prefixes::               Instruction Prefixes
* i386-Memory::                 Memory References
* i386-Jumps::                  Handling of Jump Instructions
* i386-Float::                  Floating Point
* i386-SIMD::                   Intel's MMX and AMD's 3DNow! SIMD Operations
* i386-16bit::                  Writing 16-bit Code
* i386-Arch::                   Specifying an x86 CPU architecture
* i386-Bugs::                   AT&T Syntax bugs
* i386-Notes::                  Notes


File: as.info,  Node: i386-Options,  Next: i386-Syntax,  Up: i386-Dependent

8.11.1 Options
--------------

The i386 version of `as' has a few machine dependent options:

`--32 | --64'
     Select the word size, either 32 bits or 64 bits. Selecting 32-bit
     implies Intel i386 architecture, while 64-bit implies AMD x86-64
     architecture.

     These options are only available with the ELF object file format,
     and require that the necessary BFD support has been included (on a
     32-bit platform you have to add -enable-64-bit-bfd to configure
     enable 64-bit usage and use x86-64 as target platform).

`-n'
     By default, x86 GAS replaces multiple nop instructions used for
     alignment within code sections with multi-byte nop instructions
     such as leal 0(%esi,1),%esi.  This switch disables the
     optimization.

`--divide'
     On SVR4-derived platforms, the character `/' is treated as a
     comment character, which means that it cannot be used in
     expressions.  The `--divide' option turns `/' into a normal
     character.  This does not disable `/' at the beginning of a line
     starting a comment, or affect using `#' for starting a comment.



File: as.info,  Node: i386-Syntax,  Next: i386-Mnemonics,  Prev: i386-Options,  Up: i386-Dependent

8.11.2 AT&T Syntax versus Intel Syntax
--------------------------------------

`as' now supports assembly using Intel assembler syntax.
`.intel_syntax' selects Intel mode, and `.att_syntax' switches back to
the usual AT&T mode for compatibility with the output of `gcc'.  Either
of these directives may have an optional argument, `prefix', or
`noprefix' specifying whether registers require a `%' prefix.  AT&T
System V/386 assembler syntax is quite different from Intel syntax.  We
mention these differences because almost all 80386 documents use Intel
syntax.  Notable differences between the two syntaxes are:

   * AT&T immediate operands are preceded by `$'; Intel immediate
     operands are undelimited (Intel `push 4' is AT&T `pushl $4').
     AT&T register operands are preceded by `%'; Intel register operands
     are undelimited.  AT&T absolute (as opposed to PC relative)
     jump/call operands are prefixed by `*'; they are undelimited in
     Intel syntax.

   * AT&T and Intel syntax use the opposite order for source and
     destination operands.  Intel `add eax, 4' is `addl $4, %eax'.  The
     `source, dest' convention is maintained for compatibility with
     previous Unix assemblers.  Note that instructions with more than
     one source operand, such as the `enter' instruction, do _not_ have
     reversed order.  *Note i386-Bugs::.

   * In AT&T syntax the size of memory operands is determined from the
     last character of the instruction mnemonic.  Mnemonic suffixes of
     `b', `w', `l' and `q' specify byte (8-bit), word (16-bit), long
     (32-bit) and quadruple word (64-bit) memory references.  Intel
     syntax accomplishes this by prefixing memory operands (_not_ the
     instruction mnemonics) with `byte ptr', `word ptr', `dword ptr'
     and `qword ptr'.  Thus, Intel `mov al, byte ptr FOO' is `movb FOO,
     %al' in AT&T syntax.

   * Immediate form long jumps and calls are `lcall/ljmp $SECTION,
     $OFFSET' in AT&T syntax; the Intel syntax is `call/jmp far
     SECTION:OFFSET'.  Also, the far return instruction is `lret
     $STACK-ADJUST' in AT&T syntax; Intel syntax is `ret far
     STACK-ADJUST'.

   * The AT&T assembler does not provide support for multiple section
     programs.  Unix style systems expect all programs to be single
     sections.


File: as.info,  Node: i386-Mnemonics,  Next: i386-Regs,  Prev: i386-Syntax,  Up: i386-Dependent

8.11.3 Instruction Naming
-------------------------

Instruction mnemonics are suffixed with one character modifiers which
specify the size of operands.  The letters `b', `w', `l' and `q'
specify byte, word, long and quadruple word operands.  If no suffix is
specified by an instruction then `as' tries to fill in the missing
suffix based on the destination register operand (the last one by
convention).  Thus, `mov %ax, %bx' is equivalent to `movw %ax, %bx';
also, `mov $1, %bx' is equivalent to `movw $1, bx'.  Note that this is
incompatible with the AT&T Unix assembler which assumes that a missing
mnemonic suffix implies long operand size.  (This incompatibility does
not affect compiler output since compilers always explicitly specify
the mnemonic suffix.)

   Almost all instructions have the same names in AT&T and Intel format.
There are a few exceptions.  The sign extend and zero extend
instructions need two sizes to specify them.  They need a size to
sign/zero extend _from_ and a size to zero extend _to_.  This is
accomplished by using two instruction mnemonic suffixes in AT&T syntax.
Base names for sign extend and zero extend are `movs...' and `movz...'
in AT&T syntax (`movsx' and `movzx' in Intel syntax).  The instruction
mnemonic suffixes are tacked on to this base name, the _from_ suffix
before the _to_ suffix.  Thus, `movsbl %al, %edx' is AT&T syntax for
"move sign extend _from_ %al _to_ %edx."  Possible suffixes, thus, are
`bl' (from byte to long), `bw' (from byte to word), `wl' (from word to
long), `bq' (from byte to quadruple word), `wq' (from word to quadruple
word), and `lq' (from long to quadruple word).

   The Intel-syntax conversion instructions

   * `cbw' -- sign-extend byte in `%al' to word in `%ax',

   * `cwde' -- sign-extend word in `%ax' to long in `%eax',

   * `cwd' -- sign-extend word in `%ax' to long in `%dx:%ax',

   * `cdq' -- sign-extend dword in `%eax' to quad in `%edx:%eax',

   * `cdqe' -- sign-extend dword in `%eax' to quad in `%rax' (x86-64
     only),

   * `cqo' -- sign-extend quad in `%rax' to octuple in `%rdx:%rax'
     (x86-64 only),

are called `cbtw', `cwtl', `cwtd', `cltd', `cltq', and `cqto' in AT&T
naming.  `as' accepts either naming for these instructions.

   Far call/jump instructions are `lcall' and `ljmp' in AT&T syntax,
but are `call far' and `jump far' in Intel convention.


File: as.info,  Node: i386-Regs,  Next: i386-Prefixes,  Prev: i386-Mnemonics,  Up: i386-Dependent

8.11.4 Register Naming
----------------------

Register operands are always prefixed with `%'.  The 80386 registers
consist of

   * the 8 32-bit registers `%eax' (the accumulator), `%ebx', `%ecx',
     `%edx', `%edi', `%esi', `%ebp' (the frame pointer), and `%esp'
     (the stack pointer).

   * the 8 16-bit low-ends of these: `%ax', `%bx', `%cx', `%dx', `%di',
     `%si', `%bp', and `%sp'.

   * the 8 8-bit registers: `%ah', `%al', `%bh', `%bl', `%ch', `%cl',
     `%dh', and `%dl' (These are the high-bytes and low-bytes of `%ax',
     `%bx', `%cx', and `%dx')

   * the 6 section registers `%cs' (code section), `%ds' (data
     section), `%ss' (stack section), `%es', `%fs', and `%gs'.

   * the 3 processor control registers `%cr0', `%cr2', and `%cr3'.

   * the 6 debug registers `%db0', `%db1', `%db2', `%db3', `%db6', and
     `%db7'.

   * the 2 test registers `%tr6' and `%tr7'.

   * the 8 floating point register stack `%st' or equivalently
     `%st(0)', `%st(1)', `%st(2)', `%st(3)', `%st(4)', `%st(5)',
     `%st(6)', and `%st(7)'.  These registers are overloaded by 8 MMX
     registers `%mm0', `%mm1', `%mm2', `%mm3', `%mm4', `%mm5', `%mm6'
     and `%mm7'.

   * the 8 SSE registers registers `%xmm0', `%xmm1', `%xmm2', `%xmm3',
     `%xmm4', `%xmm5', `%xmm6' and `%xmm7'.

   The AMD x86-64 architecture extends the register set by:

   * enhancing the 8 32-bit registers to 64-bit: `%rax' (the
     accumulator), `%rbx', `%rcx', `%rdx', `%rdi', `%rsi', `%rbp' (the
     frame pointer), `%rsp' (the stack pointer)

   * the 8 extended registers `%r8'-`%r15'.

   * the 8 32-bit low ends of the extended registers: `%r8d'-`%r15d'

   * the 8 16-bit low ends of the extended registers: `%r8w'-`%r15w'

   * the 8 8-bit low ends of the extended registers: `%r8b'-`%r15b'

   * the 4 8-bit registers: `%sil', `%dil', `%bpl', `%spl'.

   * the 8 debug registers: `%db8'-`%db15'.

   * the 8 SSE registers: `%xmm8'-`%xmm15'.


File: as.info,  Node: i386-Prefixes,  Next: i386-Memory,  Prev: i386-Regs,  Up: i386-Dependent

8.11.5 Instruction Prefixes
---------------------------

Instruction prefixes are used to modify the following instruction.  They
are used to repeat string instructions, to provide section overrides, to
perform bus lock operations, and to change operand and address sizes.
(Most instructions that normally operate on 32-bit operands will use
16-bit operands if the instruction has an "operand size" prefix.)
Instruction prefixes are best written on the same line as the
instruction they act upon. For example, the `scas' (scan string)
instruction is repeated with:

             repne scas %es:(%edi),%al

   You may also place prefixes on the lines immediately preceding the
instruction, but this circumvents checks that `as' does with prefixes,
and will not work with all prefixes.

   Here is a list of instruction prefixes:

   * Section override prefixes `cs', `ds', `ss', `es', `fs', `gs'.
     These are automatically added by specifying using the
     SECTION:MEMORY-OPERAND form for memory references.

   * Operand/Address size prefixes `data16' and `addr16' change 32-bit
     operands/addresses into 16-bit operands/addresses, while `data32'
     and `addr32' change 16-bit ones (in a `.code16' section) into
     32-bit operands/addresses.  These prefixes _must_ appear on the
     same line of code as the instruction they modify. For example, in
     a 16-bit `.code16' section, you might write:

                  addr32 jmpl *(%ebx)

   * The bus lock prefix `lock' inhibits interrupts during execution of
     the instruction it precedes.  (This is only valid with certain
     instructions; see a 80386 manual for details).

   * The wait for coprocessor prefix `wait' waits for the coprocessor to
     complete the current instruction.  This should never be needed for
     the 80386/80387 combination.

   * The `rep', `repe', and `repne' prefixes are added to string
     instructions to make them repeat `%ecx' times (`%cx' times if the
     current address size is 16-bits).  

   * The `rex' family of prefixes is used by x86-64 to encode
     extensions to i386 instruction set.  The `rex' prefix has four
     bits -- an operand size overwrite (`64') used to change operand
     size from 32-bit to 64-bit and X, Y and Z extensions bits used to
     extend the register set.

     You may write the `rex' prefixes directly. The `rex64xyz'
     instruction emits `rex' prefix with all the bits set.  By omitting
     the `64', `x', `y' or `z' you may write other prefixes as well.
     Normally, there is no need to write the prefixes explicitly, since
     gas will automatically generate them based on the instruction
     operands.


File: as.info,  Node: i386-Memory,  Next: i386-Jumps,  Prev: i386-Prefixes,  Up: i386-Dependent

8.11.6 Memory References
------------------------

An Intel syntax indirect memory reference of the form

     SECTION:[BASE + INDEX*SCALE + DISP]

is translated into the AT&T syntax

     SECTION:DISP(BASE, INDEX, SCALE)

where BASE and INDEX are the optional 32-bit base and index registers,
DISP is the optional displacement, and SCALE, taking the values 1, 2,
4, and 8, multiplies INDEX to calculate the address of the operand.  If
no SCALE is specified, SCALE is taken to be 1.  SECTION specifies the
optional section register for the memory operand, and may override the
default section register (see a 80386 manual for section register
defaults). Note that section overrides in AT&T syntax _must_ be
preceded by a `%'.  If you specify a section override which coincides
with the default section register, `as' does _not_ output any section
register override prefixes to assemble the given instruction.  Thus,
section overrides can be specified to emphasize which section register
is used for a given memory operand.

   Here are some examples of Intel and AT&T style memory references:

AT&T: `-4(%ebp)', Intel:  `[ebp - 4]'
     BASE is `%ebp'; DISP is `-4'. SECTION is missing, and the default
     section is used (`%ss' for addressing with `%ebp' as the base
     register).  INDEX, SCALE are both missing.

AT&T: `foo(,%eax,4)', Intel: `[foo + eax*4]'
     INDEX is `%eax' (scaled by a SCALE 4); DISP is `foo'.  All other
     fields are missing.  The section register here defaults to `%ds'.

AT&T: `foo(,1)'; Intel `[foo]'
     This uses the value pointed to by `foo' as a memory operand.  Note
     that BASE and INDEX are both missing, but there is only _one_ `,'.
     This is a syntactic exception.

AT&T: `%gs:foo'; Intel `gs:foo'
     This selects the contents of the variable `foo' with section
     register SECTION being `%gs'.

   Absolute (as opposed to PC relative) call and jump operands must be
prefixed with `*'.  If no `*' is specified, `as' always chooses PC
relative addressing for jump/call labels.

   Any instruction that has a memory operand, but no register operand,
_must_ specify its size (byte, word, long, or quadruple) with an
instruction mnemonic suffix (`b', `w', `l' or `q', respectively).

   The x86-64 architecture adds an RIP (instruction pointer relative)
addressing.  This addressing mode is specified by using `rip' as a base
register.  Only constant offsets are valid. For example:

AT&T: `1234(%rip)', Intel: `[rip + 1234]'
     Points to the address 1234 bytes past the end of the current
     instruction.

AT&T: `symbol(%rip)', Intel: `[rip + symbol]'
     Points to the `symbol' in RIP relative way, this is shorter than
     the default absolute addressing.

   Other addressing modes remain unchanged in x86-64 architecture,
except registers used are 64-bit instead of 32-bit.


File: as.info,  Node: i386-Jumps,  Next: i386-Float,  Prev: i386-Memory,  Up: i386-Dependent

8.11.7 Handling of Jump Instructions
------------------------------------

Jump instructions are always optimized to use the smallest possible
displacements.  This is accomplished by using byte (8-bit) displacement
jumps whenever the target is sufficiently close.  If a byte displacement
is insufficient a long displacement is used.  We do not support word
(16-bit) displacement jumps in 32-bit mode (i.e. prefixing the jump
instruction with the `data16' instruction prefix), since the 80386
insists upon masking `%eip' to 16 bits after the word displacement is
added. (See also *note i386-Arch::)

   Note that the `jcxz', `jecxz', `loop', `loopz', `loope', `loopnz'
and `loopne' instructions only come in byte displacements, so that if
you use these instructions (`gcc' does not use them) you may get an
error message (and incorrect code).  The AT&T 80386 assembler tries to
get around this problem by expanding `jcxz foo' to

              jcxz cx_zero
              jmp cx_nonzero
     cx_zero: jmp foo
     cx_nonzero:


File: as.info,  Node: i386-Float,  Next: i386-SIMD,  Prev: i386-Jumps,  Up: i386-Dependent

8.11.8 Floating Point
---------------------

All 80387 floating point types except packed BCD are supported.  (BCD
support may be added without much difficulty).  These data types are
16-, 32-, and 64- bit integers, and single (32-bit), double (64-bit),
and extended (80-bit) precision floating point.  Each supported type
has an instruction mnemonic suffix and a constructor associated with
it.  Instruction mnemonic suffixes specify the operand's data type.
Constructors build these data types into memory.

   * Floating point constructors are `.float' or `.single', `.double',
     and `.tfloat' for 32-, 64-, and 80-bit formats.  These correspond
     to instruction mnemonic suffixes `s', `l', and `t'. `t' stands for
     80-bit (ten byte) real.  The 80387 only supports this format via
     the `fldt' (load 80-bit real to stack top) and `fstpt' (store
     80-bit real and pop stack) instructions.

   * Integer constructors are `.word', `.long' or `.int', and `.quad'
     for the 16-, 32-, and 64-bit integer formats.  The corresponding
     instruction mnemonic suffixes are `s' (single), `l' (long), and
     `q' (quad).  As with the 80-bit real format, the 64-bit `q' format
     is only present in the `fildq' (load quad integer to stack top)
     and `fistpq' (store quad integer and pop stack) instructions.

   Register to register operations should not use instruction mnemonic
suffixes.  `fstl %st, %st(1)' will give a warning, and be assembled as
if you wrote `fst %st, %st(1)', since all register to register
operations use 80-bit floating point operands. (Contrast this with
`fstl %st, mem', which converts `%st' from 80-bit to 64-bit floating
point format, then stores the result in the 4 byte location `mem')


File: as.info,  Node: i386-SIMD,  Next: i386-16bit,  Prev: i386-Float,  Up: i386-Dependent

8.11.9 Intel's MMX and AMD's 3DNow! SIMD Operations
---------------------------------------------------

`as' supports Intel's MMX instruction set (SIMD instructions for
integer data), available on Intel's Pentium MMX processors and Pentium
II processors, AMD's K6 and K6-2 processors, Cyrix' M2 processor, and
probably others.  It also supports AMD's 3DNow!  instruction set (SIMD
instructions for 32-bit floating point data) available on AMD's K6-2
processor and possibly others in the future.

   Currently, `as' does not support Intel's floating point SIMD, Katmai
(KNI).

   The eight 64-bit MMX operands, also used by 3DNow!, are called
`%mm0', `%mm1', ... `%mm7'.  They contain eight 8-bit integers, four
16-bit integers, two 32-bit integers, one 64-bit integer, or two 32-bit
floating point values.  The MMX registers cannot be used at the same
time as the floating point stack.

   See Intel and AMD documentation, keeping in mind that the operand
order in instructions is reversed from the Intel syntax.


File: as.info,  Node: i386-16bit,  Next: i386-Arch,  Prev: i386-SIMD,  Up: i386-Dependent

8.11.10 Writing 16-bit Code
---------------------------

While `as' normally writes only "pure" 32-bit i386 code or 64-bit
x86-64 code depending on the default configuration, it also supports
writing code to run in real mode or in 16-bit protected mode code
segments.  To do this, put a `.code16' or `.code16gcc' directive before
the assembly language instructions to be run in 16-bit mode.  You can
switch `as' back to writing normal 32-bit code with the `.code32'
directive.

   `.code16gcc' provides experimental support for generating 16-bit
code from gcc, and differs from `.code16' in that `call', `ret',
`enter', `leave', `push', `pop', `pusha', `popa', `pushf', and `popf'
instructions default to 32-bit size.  This is so that the stack pointer
is manipulated in the same way over function calls, allowing access to
function parameters at the same stack offsets as in 32-bit mode.
`.code16gcc' also automatically adds address size prefixes where
necessary to use the 32-bit addressing modes that gcc generates.

   The code which `as' generates in 16-bit mode will not necessarily
run on a 16-bit pre-80386 processor.  To write code that runs on such a
processor, you must refrain from using _any_ 32-bit constructs which
require `as' to output address or operand size prefixes.

   Note that writing 16-bit code instructions by explicitly specifying a
prefix or an instruction mnemonic suffix within a 32-bit code section
generates different machine instructions than those generated for a
16-bit code segment.  In a 32-bit code section, the following code
generates the machine opcode bytes `66 6a 04', which pushes the value
`4' onto the stack, decrementing `%esp' by 2.

             pushw $4

   The same code in a 16-bit code section would generate the machine
opcode bytes `6a 04' (ie. without the operand size prefix), which is
correct since the processor default operand size is assumed to be 16
bits in a 16-bit code section.


File: as.info,  Node: i386-Bugs,  Next: i386-Notes,  Prev: i386-Arch,  Up: i386-Dependent

8.11.11 AT&T Syntax bugs
------------------------

The UnixWare assembler, and probably other AT&T derived ix86 Unix
assemblers, generate floating point instructions with reversed source
and destination registers in certain cases.  Unfortunately, gcc and
possibly many other programs use this reversed syntax, so we're stuck
with it.

   For example

             fsub %st,%st(3)
   results in `%st(3)' being updated to `%st - %st(3)' rather than the
expected `%st(3) - %st'.  This happens with all the non-commutative
arithmetic floating point operations with two register operands where
the source register is `%st' and the destination register is `%st(i)'.


File: as.info,  Node: i386-Arch,  Next: i386-Bugs,  Prev: i386-16bit,  Up: i386-Dependent

8.11.12 Specifying CPU Architecture
-----------------------------------

`as' may be told to assemble for a particular CPU (sub-)architecture
with the `.arch CPU_TYPE' directive.  This directive enables a warning
when gas detects an instruction that is not supported on the CPU
specified.  The choices for CPU_TYPE are:

`i8086'        `i186'         `i286'         `i386'
`i486'         `i586'         `i686'         `pentium'
`pentiumpro'   `pentiumii'    `pentiumiii'   `pentium4'
`k6'           `athlon'                      
               `sledgehammer'                
`.mmx' `.sse'                                
`.sse2'                                      
`.sse3'                                      
`.3dnow'                                     

   Apart from the warning, there are only two other effects on `as'
operation;  Firstly, if you specify a CPU other than `i486', then shift
by one instructions such as `sarl $1, %eax' will automatically use a
two byte opcode sequence.  The larger three byte opcode sequence is
used on the 486 (and when no architecture is specified) because it
executes faster on the 486.  Note that you can explicitly request the
two byte opcode by writing `sarl %eax'.  Secondly, if you specify
`i8086', `i186', or `i286', _and_ `.code16' or `.code16gcc' then byte
offset conditional jumps will be promoted when necessary to a two
instruction sequence consisting of a conditional jump of the opposite
sense around an unconditional jump to the target.

   Following the CPU architecture (but not a sub-architecture, which
are those starting with a dot), you may specify `jumps' or `nojumps' to
control automatic promotion of conditional jumps. `jumps' is the
default, and enables jump promotion;  All external jumps will be of the
long variety, and file-local jumps will be promoted as necessary.
(*note i386-Jumps::)  `nojumps' leaves external conditional jumps as
byte offset jumps, and warns about file-local conditional jumps that
`as' promotes.  Unconditional jumps are treated as for `jumps'.

   For example

      .arch i8086,nojumps


File: as.info,  Node: i386-Notes,  Prev: i386-Bugs,  Up: i386-Dependent

8.11.13 Notes
-------------

There is some trickery concerning the `mul' and `imul' instructions
that deserves mention.  The 16-, 32-, 64- and 128-bit expanding
multiplies (base opcode `0xf6'; extension 4 for `mul' and 5 for `imul')
can be output only in the one operand form.  Thus, `imul %ebx, %eax'
does _not_ select the expanding multiply; the expanding multiply would
clobber the `%edx' register, and this would confuse `gcc' output.  Use
`imul %ebx' to get the 64-bit product in `%edx:%eax'.

   We have added a two operand form of `imul' when the first operand is
an immediate mode expression and the second operand is a register.
This is just a shorthand, so that, multiplying `%eax' by 69, for
example, can be done with `imul $69, %eax' rather than `imul $69, %eax,
%eax'.


File: as.info,  Node: i860-Dependent,  Next: i960-Dependent,  Prev: i386-Dependent,  Up: Machine Dependencies

8.12 Intel i860 Dependent Features
==================================

* Menu:

* Notes-i860::                  i860 Notes
* Options-i860::                i860 Command-line Options
* Directives-i860::             i860 Machine Directives
* Opcodes for i860::            i860 Opcodes


File: as.info,  Node: Notes-i860,  Next: Options-i860,  Up: i860-Dependent

8.12.1 i860 Notes
-----------------

This is a fairly complete i860 assembler which is compatible with the
UNIX System V/860 Release 4 assembler. However, it does not currently
support SVR4 PIC (i.e., `@GOT, @GOTOFF, @PLT').

   Like the SVR4/860 assembler, the output object format is ELF32.
Currently, this is the only supported object format. If there is
sufficient interest, other formats such as COFF may be implemented.

   Both the Intel and AT&T/SVR4 syntaxes are supported, with the latter
being the default.  One difference is that AT&T syntax requires the '%'
prefix on register names while Intel syntax does not.  Another
difference is in the specification of relocatable expressions.  The
Intel syntax is `ha%expression' whereas the SVR4 syntax is
`[expression]@ha' (and similarly for the "l" and "h" selectors).


File: as.info,  Node: Options-i860,  Next: Directives-i860,  Prev: Notes-i860,  Up: i860-Dependent

8.12.2 i860 Command-line Options
--------------------------------

8.12.2.1 SVR4 compatibility options
...................................

`-V'
     Print assembler version.

`-Qy'
     Ignored.

`-Qn'
     Ignored.

8.12.2.2 Other options
......................

`-EL'
     Select little endian output (this is the default).

`-EB'
     Select big endian output. Note that the i860 always reads
     instructions as little endian data, so this option only effects
     data and not instructions.

`-mwarn-expand'
     Emit a warning message if any pseudo-instruction expansions
     occurred.  For example, a `or' instruction with an immediate
     larger than 16-bits will be expanded into two instructions. This
     is a very undesirable feature to rely on, so this flag can help
     detect any code where it happens. One use of it, for instance, has
     been to find and eliminate any place where `gcc' may emit these
     pseudo-instructions.

`-mxp'
     Enable support for the i860XP instructions and control registers.
     By default, this option is disabled so that only the base
     instruction set (i.e., i860XR) is supported.

`-mintel-syntax'
     The i860 assembler defaults to AT&T/SVR4 syntax.  This option
     enables the Intel syntax.


File: as.info,  Node: Directives-i860,  Next: Opcodes for i860,  Prev: Options-i860,  Up: i860-Dependent

8.12.3 i860 Machine Directives
------------------------------

`.dual'
     Enter dual instruction mode. While this directive is supported, the
     preferred way to use dual instruction mode is to explicitly code
     the dual bit with the `d.' prefix.

`.enddual'
     Exit dual instruction mode. While this directive is supported, the
     preferred way to use dual instruction mode is to explicitly code
     the dual bit with the `d.' prefix.

`.atmp'
     Change the temporary register used when expanding pseudo
     operations. The default register is `r31'.

   The `.dual', `.enddual', and `.atmp' directives are available only
in the Intel syntax mode.

   Both syntaxes allow for the standard `.align' directive.  However,
the Intel syntax additionally allows keywords for the alignment
parameter: "`.align type'", where `type' is one of `.short', `.long',
`.quad', `.single', `.double' representing alignments of 2, 4, 16, 4,
and 8, respectively.


File: as.info,  Node: Opcodes for i860,  Prev: Directives-i860,  Up: i860-Dependent

8.12.4 i860 Opcodes
-------------------

All of the Intel i860XR and i860XP machine instructions are supported.
Please see either _i860 Microprocessor Programmer's Reference Manual_
or _i860 Microprocessor Architecture_ for more information.

8.12.4.1 Other instruction support (pseudo-instructions)
........................................................

For compatibility with some other i860 assemblers, a number of
pseudo-instructions are supported. While these are supported, they are
a very undesirable feature that should be avoided - in particular, when
they result in an expansion to multiple actual i860 instructions. Below
are the pseudo-instructions that result in expansions.
   * Load large immediate into general register:

     The pseudo-instruction `mov imm,%rn' (where the immediate does not
     fit within a signed 16-bit field) will be expanded into:
          orh large_imm@h,%r0,%rn
          or large_imm@l,%rn,%rn

   * Load/store with relocatable address expression:

     For example, the pseudo-instruction `ld.b addr_exp(%rx),%rn' will
     be expanded into:
          orh addr_exp@ha,%rx,%r31
          ld.l addr_exp@l(%r31),%rn

     The analogous expansions apply to `ld.x, st.x, fld.x, pfld.x,
     fst.x', and `pst.x' as well.

   * Signed large immediate with add/subtract:

     If any of the arithmetic operations `adds, addu, subs, subu' are
     used with an immediate larger than 16-bits (signed), then they
     will be expanded.  For instance, the pseudo-instruction `adds
     large_imm,%rx,%rn' expands to:
          orh large_imm@h,%r0,%r31
          or large_imm@l,%r31,%r31
          adds %r31,%rx,%rn

   * Unsigned large immediate with logical operations:

     Logical operations (`or, andnot, or, xor') also result in
     expansions.  The pseudo-instruction `or large_imm,%rx,%rn' results
     in:
          orh large_imm@h,%rx,%r31
          or large_imm@l,%r31,%rn

     Similarly for the others, except for `and' which expands to:
          andnot (-1 - large_imm)@h,%rx,%r31
          andnot (-1 - large_imm)@l,%r31,%rn


File: as.info,  Node: i960-Dependent,  Next: IA-64-Dependent,  Prev: i860-Dependent,  Up: Machine Dependencies

8.13 Intel 80960 Dependent Features
===================================

* Menu:

* Options-i960::                i960 Command-line Options
* Floating Point-i960::         Floating Point
* Directives-i960::             i960 Machine Directives
* Opcodes for i960::            i960 Opcodes


File: as.info,  Node: Options-i960,  Next: Floating Point-i960,  Up: i960-Dependent

8.13.1 i960 Command-line Options
--------------------------------

`-ACA | -ACA_A | -ACB | -ACC | -AKA | -AKB | -AKC | -AMC'
     Select the 80960 architecture.  Instructions or features not
     supported by the selected architecture cause fatal errors.

     `-ACA' is equivalent to `-ACA_A'; `-AKC' is equivalent to `-AMC'.
     Synonyms are provided for compatibility with other tools.

     If you do not specify any of these options, `as' generates code
     for any instruction or feature that is supported by _some_ version
     of the 960 (even if this means mixing architectures!).  In
     principle, `as' attempts to deduce the minimal sufficient
     processor type if none is specified; depending on the object code
     format, the processor type may be recorded in the object file.  If
     it is critical that the `as' output match a specific architecture,
     specify that architecture explicitly.

`-b'
     Add code to collect information about conditional branches taken,
     for later optimization using branch prediction bits.  (The
     conditional branch instructions have branch prediction bits in the
     CA, CB, and CC architectures.)  If BR represents a conditional
     branch instruction, the following represents the code generated by
     the assembler when `-b' is specified:

                  call    INCREMENT ROUTINE
                  .word   0       # pre-counter
          Label:  BR
                  call    INCREMENT ROUTINE
                  .word   0       # post-counter

     The counter following a branch records the number of times that
     branch was _not_ taken; the differenc between the two counters is
     the number of times the branch _was_ taken.

     A table of every such `Label' is also generated, so that the
     external postprocessor `gbr960' (supplied by Intel) can locate all
     the counters.  This table is always labeled `__BRANCH_TABLE__';
     this is a local symbol to permit collecting statistics for many
     separate object files.  The table is word aligned, and begins with
     a two-word header.  The first word, initialized to 0, is used in
     maintaining linked lists of branch tables.  The second word is a
     count of the number of entries in the table, which follow
     immediately: each is a word, pointing to one of the labels
     illustrated above.

           +------------+------------+------------+ ... +------------+
           |            |            |            |     |            |
           |  *NEXT     |  COUNT: N  | *BRLAB 1   |     | *BRLAB N   |
           |            |            |            |     |            |
           +------------+------------+------------+ ... +------------+

                         __BRANCH_TABLE__ layout

     The first word of the header is used to locate multiple branch
     tables, since each object file may contain one. Normally the links
     are maintained with a call to an initialization routine, placed at
     the beginning of each function in the file.  The GNU C compiler
     generates these calls automatically when you give it a `-b' option.
     For further details, see the documentation of `gbr960'.

`-no-relax'
     Normally, Compare-and-Branch instructions with targets that require
     displacements greater than 13 bits (or that have external targets)
     are replaced with the corresponding compare (or `chkbit') and
     branch instructions.  You can use the `-no-relax' option to
     specify that `as' should generate errors instead, if the target
     displacement is larger than 13 bits.

     This option does not affect the Compare-and-Jump instructions; the
     code emitted for them is _always_ adjusted when necessary
     (depending on displacement size), regardless of whether you use
     `-no-relax'.


File: as.info,  Node: Floating Point-i960,  Next: Directives-i960,  Prev: Options-i960,  Up: i960-Dependent

8.13.2 Floating Point
---------------------

`as' generates IEEE floating-point numbers for the directives `.float',
`.double', `.extended', and `.single'.


File: as.info,  Node: Directives-i960,  Next: Opcodes for i960,  Prev: Floating Point-i960,  Up: i960-Dependent

8.13.3 i960 Machine Directives
------------------------------

`.bss SYMBOL, LENGTH, ALIGN'
     Reserve LENGTH bytes in the bss section for a local SYMBOL,
     aligned to the power of two specified by ALIGN.  LENGTH and ALIGN
     must be positive absolute expressions.  This directive differs
     from `.lcomm' only in that it permits you to specify an alignment.
     *Note `.lcomm': Lcomm.

`.extended FLONUMS'
     `.extended' expects zero or more flonums, separated by commas; for
     each flonum, `.extended' emits an IEEE extended-format (80-bit)
     floating-point number.

`.leafproc CALL-LAB, BAL-LAB'
     You can use the `.leafproc' directive in conjunction with the
     optimized `callj' instruction to enable faster calls of leaf
     procedures.  If a procedure is known to call no other procedures,
     you may define an entry point that skips procedure prolog code
     (and that does not depend on system-supplied saved context), and
     declare it as the BAL-LAB using `.leafproc'.  If the procedure
     also has an entry point that goes through the normal prolog, you
     can specify that entry point as CALL-LAB.

     A `.leafproc' declaration is meant for use in conjunction with the
     optimized call instruction `callj'; the directive records the data
     needed later to choose between converting the `callj' into a `bal'
     or a `call'.

     CALL-LAB is optional; if only one argument is present, or if the
     two arguments are identical, the single argument is assumed to be
     the `bal' entry point.

`.sysproc NAME, INDEX'
     The `.sysproc' directive defines a name for a system procedure.
     After you define it using `.sysproc', you can use NAME to refer to
     the system procedure identified by INDEX when calling procedures
     with the optimized call instruction `callj'.

     Both arguments are required; INDEX must be between 0 and 31
     (inclusive).


File: as.info,  Node: Opcodes for i960,  Prev: Directives-i960,  Up: i960-Dependent

8.13.4 i960 Opcodes
-------------------

All Intel 960 machine instructions are supported; *note i960
Command-line Options: Options-i960. for a discussion of selecting the
instruction subset for a particular 960 architecture.

   Some opcodes are processed beyond simply emitting a single
corresponding instruction: `callj', and Compare-and-Branch or
Compare-and-Jump instructions with target displacements larger than 13
bits.

* Menu:

* callj-i960::                  `callj'
* Compare-and-branch-i960::     Compare-and-Branch


File: as.info,  Node: callj-i960,  Next: Compare-and-branch-i960,  Up: Opcodes for i960

8.13.4.1 `callj'
................

You can write `callj' to have the assembler or the linker determine the
most appropriate form of subroutine call: `call', `bal', or `calls'.
If the assembly source contains enough information--a `.leafproc' or
`.sysproc' directive defining the operand--then `as' translates the
`callj'; if not, it simply emits the `callj', leaving it for the linker
to resolve.


File: as.info,  Node: Compare-and-branch-i960,  Prev: callj-i960,  Up: Opcodes for i960

8.13.4.2 Compare-and-Branch
...........................

The 960 architectures provide combined Compare-and-Branch instructions
that permit you to store the branch target in the lower 13 bits of the
instruction word itself.  However, if you specify a branch target far
enough away that its address won't fit in 13 bits, the assembler can
either issue an error, or convert your Compare-and-Branch instruction
into separate instructions to do the compare and the branch.

   Whether `as' gives an error or expands the instruction depends on
two choices you can make: whether you use the `-no-relax' option, and
whether you use a "Compare and Branch" instruction or a "Compare and
Jump" instruction.  The "Jump" instructions are _always_ expanded if
necessary; the "Branch" instructions are expanded when necessary
_unless_ you specify `-no-relax'--in which case `as' gives an error
instead.

   These are the Compare-and-Branch instructions, their "Jump" variants,
and the instruction pairs they may expand into:

             Compare and
          Branch      Jump       Expanded to
          ------    ------       ------------
             bbc                 chkbit; bno
             bbs                 chkbit; bo
          cmpibe    cmpije       cmpi; be
          cmpibg    cmpijg       cmpi; bg
         cmpibge   cmpijge       cmpi; bge
          cmpibl    cmpijl       cmpi; bl
         cmpible   cmpijle       cmpi; ble
         cmpibno   cmpijno       cmpi; bno
         cmpibne   cmpijne       cmpi; bne
          cmpibo    cmpijo       cmpi; bo
          cmpobe    cmpoje       cmpo; be
          cmpobg    cmpojg       cmpo; bg
         cmpobge   cmpojge       cmpo; bge
          cmpobl    cmpojl       cmpo; bl
         cmpoble   cmpojle       cmpo; ble
         cmpobne   cmpojne       cmpo; bne


File: as.info,  Node: IA-64-Dependent,  Next: IP2K-Dependent,  Prev: i960-Dependent,  Up: Machine Dependencies

8.14 IA-64 Dependent Features
=============================

* Menu:

* IA-64 Options::              Options
* IA-64 Syntax::               Syntax
* IA-64 Opcodes::              Opcodes


File: as.info,  Node: IA-64 Options,  Next: IA-64 Syntax,  Up: IA-64-Dependent

8.14.1 Options
--------------

`-mconstant-gp'
     This option instructs the assembler to mark the resulting object
     file as using the "constant GP" model.  With this model, it is
     assumed that the entire program uses a single global pointer (GP)
     value.  Note that this option does not in any fashion affect the
     machine code emitted by the assembler.  All it does is turn on the
     EF_IA_64_CONS_GP flag in the ELF file header.

`-mauto-pic'
     This option instructs the assembler to mark the resulting object
     file as using the "constant GP without function descriptor" data
     model.  This model is like the "constant GP" model, except that it
     additionally does away with function descriptors.  What this means
     is that the address of a function refers directly to the
     function's code entry-point.  Normally, such an address would
     refer to a function descriptor, which contains both the code
     entry-point and the GP-value needed by the function.  Note that
     this option does not in any fashion affect the machine code
     emitted by the assembler.  All it does is turn on the
     EF_IA_64_NOFUNCDESC_CONS_GP flag in the ELF file header.

`-milp32'

`-milp64'

`-mlp64'

`-mp64'
     These options select the data model.  The assembler defaults to
     `-mlp64' (LP64 data model).

`-mle'

`-mbe'
     These options select the byte order.  The `-mle' option selects
     little-endian byte order (default) and `-mbe' selects big-endian
     byte order.  Note that IA-64 machine code always uses
     little-endian byte order.

`-mtune=itanium1'

`-mtune=itanium2'
     Tune for a particular IA-64 CPU, ITANIUM1 or ITANIUM2. The default
     is ITANIUM2.

`-munwind-check=warning'

`-munwind-check=error'
     These options control what the assembler will do when performing
     consistency checks on unwind directives.  `-munwind-check=warning'
     will make the assembler issue a warning when an unwind directive
     check fails.  This is the default.  `-munwind-check=error' will
     make the assembler issue an error when an unwind directive check
     fails.

`-mhint.b=ok'

`-mhint.b=warning'

`-mhint.b=error'
     These options control what the assembler will do when the `hint.b'
     instruction is used.  `-mhint.b=ok' will make the assembler accept
     `hint.b'.  `-mint.b=warning' will make the assembler issue a
     warning when `hint.b' is used.  `-mhint.b=error' will make the
     assembler treat `hint.b' as an error, which is the default.

`-x'

`-xexplicit'
     These options turn on dependency violation checking.

`-xauto'
     This option instructs the assembler to automatically insert stop
     bits where necessary to remove dependency violations.  This is the
     default mode.

`-xnone'
     This option turns off dependency violation checking.

`-xdebug'
     This turns on debug output intended to help tracking down bugs in
     the dependency violation checker.

`-xdebugn'
     This is a shortcut for -xnone -xdebug.

`-xdebugx'
     This is a shortcut for -xexplicit -xdebug.



File: as.info,  Node: IA-64 Syntax,  Next: IA-64 Opcodes,  Prev: IA-64 Options,  Up: IA-64-Dependent

8.14.2 Syntax
-------------

The assembler syntax closely follows the IA-64 Assembly Language
Reference Guide.

* Menu:

* IA-64-Chars::                Special Characters
* IA-64-Regs::                 Register Names
* IA-64-Bits::                 Bit Names


File: as.info,  Node: IA-64-Chars,  Next: IA-64-Regs,  Up: IA-64 Syntax

8.14.2.1 Special Characters
...........................

`//' is the line comment token.

   `;' can be used instead of a newline to separate statements.


File: as.info,  Node: IA-64-Regs,  Next: IA-64-Bits,  Prev: IA-64-Chars,  Up: IA-64 Syntax

8.14.2.2 Register Names
.......................

The 128 integer registers are referred to as `rN'.  The 128
floating-point registers are referred to as `fN'.  The 128 application
registers are referred to as `arN'.  The 128 control registers are
referred to as `crN'.  The 64 one-bit predicate registers are referred
to as `pN'.  The 8 branch registers are referred to as `bN'.  In
addition, the assembler defines a number of aliases: `gp' (`r1'), `sp'
(`r12'), `rp' (`b0'), `ret0' (`r8'), `ret1' (`r9'), `ret2' (`r10'),
`ret3' (`r9'), `fargN' (`f8+N'), and `fretN' (`f8+N').

   For convenience, the assembler also defines aliases for all named
application and control registers.  For example, `ar.bsp' refers to the
register backing store pointer (`ar17').  Similarly, `cr.eoi' refers to
the end-of-interrupt register (`cr67').


File: as.info,  Node: IA-64-Bits,  Prev: IA-64-Regs,  Up: IA-64 Syntax

8.14.2.3 IA-64 Processor-Status-Register (PSR) Bit Names
........................................................

The assembler defines bit masks for each of the bits in the IA-64
processor status register.  For example, `psr.ic' corresponds to a
value of 0x2000.  These masks are primarily intended for use with the
`ssm'/`sum' and `rsm'/`rum' instructions, but they can be used anywhere
else where an integer constant is expected.


File: as.info,  Node: IA-64 Opcodes,  Prev: IA-64 Syntax,  Up: IA-64-Dependent

8.14.3 Opcodes
--------------

For detailed information on the IA-64 machine instruction set, see the
IA-64 Architecture Handbook
(http://developer.intel.com/design/itanium/arch_spec.htm).


File: as.info,  Node: IP2K-Dependent,  Next: M32C-Dependent,  Prev: IA-64-Dependent,  Up: Machine Dependencies

8.15 IP2K Dependent Features
============================

* Menu:

* IP2K-Opts::                   IP2K Options


File: as.info,  Node: IP2K-Opts,  Up: IP2K-Dependent

8.15.1 IP2K Options
-------------------

The Ubicom IP2K version of `as' has a few machine dependent options:

`-mip2022ext'
     `as' can assemble the extended IP2022 instructions, but it will
     only do so if this is specifically allowed via this command line
     option.

`-mip2022'
     This option restores the assembler's default behaviour of not
     permitting the extended IP2022 instructions to be assembled.



File: as.info,  Node: M32C-Dependent,  Next: M32R-Dependent,  Prev: IP2K-Dependent,  Up: Machine Dependencies

8.16 M32C Dependent Features
============================

   `as' can assemble code for several different members of the Renesas
M32C family.  Normally the default is to assemble code for the M16C
microprocessor.  The `-m32c' option may be used to change the default
to the M32C microprocessor.

* Menu:

* M32C-Opts::                   M32C Options
* M32C-Modifiers::              Symbolic Operand Modifiers


File: as.info,  Node: M32C-Opts,  Next: M32C-Modifiers,  Up: M32C-Dependent

8.16.1 M32C Options
-------------------

The Renesas M32C version of `as' has two machine-dependent options:

`-m32c'
     Assemble M32C instructions.

`-m16c'
     Assemble M16C instructions (default).



File: as.info,  Node: M32C-Modifiers,  Prev: M32C-Opts,  Up: M32C-Dependent

8.16.2 Symbolic Operand Modifiers
---------------------------------

The assembler supports several modifiers when using symbol addresses in
M32C instruction operands.  The general syntax is the following:

     %modifier(symbol)

`%dsp8'
`%dsp16'
     These modifiers override the assembler's assumptions about how big
     a symbol's address is.  Normally, when it sees an operand like
     `sym[a0]' it assumes `sym' may require the widest displacement
     field (16 bits for `-m16c', 24 bits for `-m32c').  These modifiers
     tell it to assume the address will fit in an 8 or 16 bit
     (respectively) unsigned displacement.  Note that, of course, if it
     doesn't actually fit you will get linker errors.  Example:

          mov.w %dsp8(sym)[a0],r1
          mov.b #0,%dsp8(sym)[a0]

`%hi8'
     This modifier allows you to load bits 16 through 23 of a 24 bit
     address into an 8 bit register.  This is useful with, for example,
     the M16C `smovf' instruction, which expects a 20 bit address in
     `r1h' and `a0'.  Example:

          mov.b #%hi8(sym),r1h
          mov.w #%lo16(sym),a0
          smovf.b

`%lo16'
     Likewise, this modifier allows you to load bits 0 through 15 of a
     24 bit address into a 16 bit register.

`%hi16'
     This modifier allows you to load bits 16 through 31 of a 32 bit
     address into a 16 bit register.  While the M32C family only has 24
     bits of address space, it does support addresses in pairs of 16 bit
     registers (like `a1a0' for the `lde' instruction).  This modifier
     is for loading the upper half in such cases.  Example:

          mov.w #%hi16(sym),a1
          mov.w #%lo16(sym),a0
          ...
          lde.w [a1a0],r1



File: as.info,  Node: M32R-Dependent,  Next: M68K-Dependent,  Prev: M32C-Dependent,  Up: Machine Dependencies

8.17 M32R Dependent Features
============================

* Menu:

* M32R-Opts::                   M32R Options
* M32R-Directives::             M32R Directives
* M32R-Warnings::               M32R Warnings


File: as.info,  Node: M32R-Opts,  Next: M32R-Directives,  Up: M32R-Dependent

8.17.1 M32R Options
-------------------

The Renease M32R version of `as' has a few machine dependent options:

`-m32rx'
     `as' can assemble code for several different members of the
     Renesas M32R family.  Normally the default is to assemble code for
     the M32R microprocessor.  This option may be used to change the
     default to the M32RX microprocessor, which adds some more
     instructions to the basic M32R instruction set, and some
     additional parameters to some of the original instructions.

`-m32r2'
     This option changes the target processor to the the M32R2
     microprocessor.

`-m32r'
     This option can be used to restore the assembler's default
     behaviour of assembling for the M32R microprocessor.  This can be
     useful if the default has been changed by a previous command line
     option.

`-little'
     This option tells the assembler to produce little-endian code and
     data.  The default is dependent upon how the toolchain was
     configured.

`-EL'
     This is a synonum for _-little_.

`-big'
     This option tells the assembler to produce big-endian code and
     data.

`-EB'
     This is a synonum for _-big_.

`-KPIC'
     This option specifies that the output of the assembler should be
     marked as position-independent code (PIC).

`-parallel'
     This option tells the assembler to attempts to combine two
     sequential instructions into a single, parallel instruction, where
     it is legal to do so.

`-no-parallel'
     This option disables a previously enabled _-parallel_ option.

`-no-bitinst'
     This option disables the support for the extended bit-field
     instructions provided by the M32R2.  If this support needs to be
     re-enabled the _-bitinst_ switch can be used to restore it.

`-O'
     This option tells the assembler to attempt to optimize the
     instructions that it produces.  This includes filling delay slots
     and converting sequential instructions into parallel ones.  This
     option implies _-parallel_.

`-warn-explicit-parallel-conflicts'
     Instructs `as' to produce warning messages when questionable
     parallel instructions are encountered.  This option is enabled by
     default, but `gcc' disables it when it invokes `as' directly.
     Questionable instructions are those whoes behaviour would be
     different if they were executed sequentially.  For example the
     code fragment `mv r1, r2 || mv r3, r1' produces a different result
     from `mv r1, r2 \n mv r3, r1' since the former moves r1 into r3
     and then r2 into r1, whereas the later moves r2 into r1 and r3.

`-Wp'
     This is a shorter synonym for the
     _-warn-explicit-parallel-conflicts_ option.

`-no-warn-explicit-parallel-conflicts'
     Instructs `as' not to produce warning messages when questionable
     parallel instructions are encountered.

`-Wnp'
     This is a shorter synonym for the
     _-no-warn-explicit-parallel-conflicts_ option.

`-ignore-parallel-conflicts'
     This option tells the assembler's to stop checking parallel
     instructions for contraint violations.  This ability is provided
     for hardware vendors testing chip designs and should not be used
     under normal circumstances.

`-no-ignore-parallel-conflicts'
     This option restores the assembler's default behaviour of checking
     parallel instructions to detect constraint violations.

`-Ip'
     This is a shorter synonym for the _-ignore-parallel-conflicts_
     option.

`-nIp'
     This is a shorter synonym for the _-no-ignore-parallel-conflicts_
     option.

`-warn-unmatched-high'
     This option tells the assembler to produce a warning message if a
     `.high' pseudo op is encountered without a mathcing `.low' pseudo
     op.  The presence of such an unmatches pseudo op usually indicates
     a programming error.

`-no-warn-unmatched-high'
     Disables a previously enabled _-warn-unmatched-high_ option.

`-Wuh'
     This is a shorter synonym for the _-warn-unmatched-high_ option.

`-Wnuh'
     This is a shorter synonym for the _-no-warn-unmatched-high_ option.



File: as.info,  Node: M32R-Directives,  Next: M32R-Warnings,  Prev: M32R-Opts,  Up: M32R-Dependent

8.17.2 M32R Directives
----------------------

The Renease M32R version of `as' has a few architecture specific
directives:

`low EXPRESSION'
     The `low' directive computes the value of its expression and
     places the lower 16-bits of the result into the immediate-field of
     the instruction.  For example:

             or3   r0, r0, #low(0x12345678) ; compute r0 = r0 | 0x5678
             add3, r0, r0, #low(fred)   ; compute r0 = r0 + low 16-bits of address of fred

`high EXPRESSION'
     The `high' directive computes the value of its expression and
     places the upper 16-bits of the result into the immediate-field of
     the instruction.  For example:

             seth  r0, #high(0x12345678) ; compute r0 = 0x12340000
             seth, r0, #high(fred)       ; compute r0 = upper 16-bits of address of fred

`shigh EXPRESSION'
     The `shigh' directive is very similar to the `high' directive.  It
     also computes the value of its expression and places the upper
     16-bits of the result into the immediate-field of the instruction.
     The difference is that `shigh' also checks to see if the lower
     16-bits could be interpreted as a signed number, and if so it
     assumes that a borrow will occur from the upper-16 bits.  To
     compensate for this the `shigh' directive pre-biases the upper 16
     bit value by adding one to it.  For example:

     For example:

             seth  r0, #shigh(0x12345678) ; compute r0 = 0x12340000
             seth  r0, #shigh(0x00008000) ; compute r0 = 0x00010000

     In the second example the lower 16-bits are 0x8000.  If these are
     treated as a signed value and sign extended to 32-bits then the
     value becomes 0xffff8000.  If this value is then added to
     0x00010000 then the result is 0x00008000.

     This behaviour is to allow for the different semantics of the
     `or3' and `add3' instructions.  The `or3' instruction treats its
     16-bit immediate argument as unsigned whereas the `add3' treats
     its 16-bit immediate as a signed value.  So for example:

             seth  r0, #shigh(0x00008000)
             add3  r0, r0, #low(0x00008000)

     Produces the correct result in r0, whereas:

             seth  r0, #shigh(0x00008000)
             or3   r0, r0, #low(0x00008000)

     Stores 0xffff8000 into r0.

     Note - the `shigh' directive does not know where in the assembly
     source code the lower 16-bits of the value are going set, so it
     cannot check to make sure that an `or3' instruction is being used
     rather than an `add3' instruction.  It is up to the programmer to
     make sure that correct directives are used.

`.m32r'
     The directive performs a similar thing as the _-m32r_ command line
     option.  It tells the assembler to only accept M32R instructions
     from now on.  An instructions from later M32R architectures are
     refused.

`.m32rx'
     The directive performs a similar thing as the _-m32rx_ command
     line option.  It tells the assembler to start accepting the extra
     instructions in the M32RX ISA as well as the ordinary M32R ISA.

`.m32r2'
     The directive performs a similar thing as the _-m32r2_ command
     line option.  It tells the assembler to start accepting the extra
     instructions in the M32R2 ISA as well as the ordinary M32R ISA.

`.little'
     The directive performs a similar thing as the _-little_ command
     line option.  It tells the assembler to start producing
     little-endian code and data.  This option should be used with care
     as producing mixed-endian binary files is frought with danger.

`.big'
     The directive performs a similar thing as the _-big_ command line
     option.  It tells the assembler to start producing big-endian code
     and data.  This option should be used with care as producing
     mixed-endian binary files is frought with danger.



File: as.info,  Node: M32R-Warnings,  Prev: M32R-Directives,  Up: M32R-Dependent

8.17.3 M32R Warnings
--------------------

There are several warning and error messages that can be produced by
`as' which are specific to the M32R:

`output of 1st instruction is the same as an input to 2nd instruction - is this intentional ?'
     This message is only produced if warnings for explicit parallel
     conflicts have been enabled.  It indicates that the assembler has
     encountered a parallel instruction in which the destination
     register of the left hand instruction is used as an input register
     in the right hand instruction.  For example in this code fragment
     `mv r1, r2 || neg r3, r1' register r1 is the destination of the
     move instruction and the input to the neg instruction.

`output of 2nd instruction is the same as an input to 1st instruction - is this intentional ?'
     This message is only produced if warnings for explicit parallel
     conflicts have been enabled.  It indicates that the assembler has
     encountered a parallel instruction in which the destination
     register of the right hand instruction is used as an input
     register in the left hand instruction.  For example in this code
     fragment `mv r1, r2 || neg r2, r3' register r2 is the destination
     of the neg instruction and the input to the move instruction.

`instruction `...' is for the M32RX only'
     This message is produced when the assembler encounters an
     instruction which is only supported by the M32Rx processor, and
     the `-m32rx' command line flag has not been specified to allow
     assembly of such instructions.

`unknown instruction `...''
     This message is produced when the assembler encounters an
     instruction which it does not recognise.

`only the NOP instruction can be issued in parallel on the m32r'
     This message is produced when the assembler encounters a parallel
     instruction which does not involve a NOP instruction and the
     `-m32rx' command line flag has not been specified.  Only the M32Rx
     processor is able to execute two instructions in parallel.

`instruction `...' cannot be executed in parallel.'
     This message is produced when the assembler encounters a parallel
     instruction which is made up of one or two instructions which
     cannot be executed in parallel.

`Instructions share the same execution pipeline'
     This message is produced when the assembler encounters a parallel
     instruction whoes components both use the same execution pipeline.

`Instructions write to the same destination register.'
     This message is produced when the assembler encounters a parallel
     instruction where both components attempt to modify the same
     register.  For example these code fragments will produce this
     message: `mv r1, r2 || neg r1, r3' `jl r0 || mv r14, r1' `st r2,
     @-r1 || mv r1, r3' `mv r1, r2 || ld r0, @r1+' `cmp r1, r2 || addx
     r3, r4' (Both write to the condition bit)



File: as.info,  Node: M68K-Dependent,  Next: M68HC11-Dependent,  Prev: M32R-Dependent,  Up: Machine Dependencies

8.18 M680x0 Dependent Features
==============================

* Menu:

* M68K-Opts::                   M680x0 Options
* M68K-Syntax::                 Syntax
* M68K-Moto-Syntax::            Motorola Syntax
* M68K-Float::                  Floating Point
* M68K-Directives::             680x0 Machine Directives
* M68K-opcodes::                Opcodes


File: as.info,  Node: M68K-Opts,  Next: M68K-Syntax,  Up: M68K-Dependent

8.18.1 M680x0 Options
---------------------

The Motorola 680x0 version of `as' has a few machine dependent options:

`-march=ARCHITECTURE'
     This option specifies a target architecture.  The following
     architectures are recognized: `68000', `68010', `68020', `68030',
     `68040', `68060', `cpu32', `isaa', `isaaplus', `isab' and `cfv4e'.

`-mcpu=CPU'
     This option specifies a target cpu.  When used in conjunction with
     the `-march' option, the cpu must be within the specified
     architecture.  Also, the generic features of the architecture are
     used for instruction generation, rather than those of the specific
     chip.

`-m[no-]68851'

`-m[no-]68881'

`-m[no-]div'

`-m[no-]usp'

`-m[no-]float'

`-m[no-]mac'

`-m[no-]emac'
     Enable or disable various architecture specific features.  If a
     chip or architecture by default supports an option (for instance
     `-march=isaaplus' includes the `-mdiv' option), explicitly
     disabling the option will override the default.

`-l'
     You can use the `-l' option to shorten the size of references to
     undefined symbols.  If you do not use the `-l' option, references
     to undefined symbols are wide enough for a full `long' (32 bits).
     (Since `as' cannot know where these symbols end up, `as' can only
     allocate space for the linker to fill in later.  Since `as' does
     not know how far away these symbols are, it allocates as much
     space as it can.)  If you use this option, the references are only
     one word wide (16 bits).  This may be useful if you want the
     object file to be as small as possible, and you know that the
     relevant symbols are always less than 17 bits away.

`--register-prefix-optional'
     For some configurations, especially those where the compiler
     normally does not prepend an underscore to the names of user
     variables, the assembler requires a `%' before any use of a
     register name.  This is intended to let the assembler distinguish
     between C variables and functions named `a0' through `a7', and so
     on.  The `%' is always accepted, but is not required for certain
     configurations, notably `sun3'.  The `--register-prefix-optional'
     option may be used to permit omitting the `%' even for
     configurations for which it is normally required.  If this is
     done, it will generally be impossible to refer to C variables and
     functions with the same names as register names.

`--bitwise-or'
     Normally the character `|' is treated as a comment character, which
     means that it can not be used in expressions.  The `--bitwise-or'
     option turns `|' into a normal character.  In this mode, you must
     either use C style comments, or start comments with a `#' character
     at the beginning of a line.

`--base-size-default-16  --base-size-default-32'
     If you use an addressing mode with a base register without
     specifying the size, `as' will normally use the full 32 bit value.
     For example, the addressing mode `%a0@(%d0)' is equivalent to
     `%a0@(%d0:l)'.  You may use the `--base-size-default-16' option to
     tell `as' to default to using the 16 bit value.  In this case,
     `%a0@(%d0)' is equivalent to `%a0@(%d0:w)'.  You may use the
     `--base-size-default-32' option to restore the default behaviour.

`--disp-size-default-16  --disp-size-default-32'
     If you use an addressing mode with a displacement, and the value
     of the displacement is not known, `as' will normally assume that
     the value is 32 bits.  For example, if the symbol `disp' has not
     been defined, `as' will assemble the addressing mode
     `%a0@(disp,%d0)' as though `disp' is a 32 bit value.  You may use
     the `--disp-size-default-16' option to tell `as' to instead assume
     that the displacement is 16 bits.  In this case, `as' will
     assemble `%a0@(disp,%d0)' as though `disp' is a 16 bit value.  You
     may use the `--disp-size-default-32' option to restore the default
     behaviour.

`--pcrel'
     Always keep branches PC-relative.  In the M680x0 architecture all
     branches are defined as PC-relative.  However, on some processors
     they are limited to word displacements maximum.  When `as' needs a
     long branch that is not available, it normally emits an absolute
     jump instead.  This option disables this substitution.  When this
     option is given and no long branches are available, only word
     branches will be emitted.  An error message will be generated if a
     word branch cannot reach its target.  This option has no effect on
     68020 and other processors that have long branches.  *note Branch
     Improvement: M68K-Branch.

`-m68000'
     `as' can assemble code for several different members of the
     Motorola 680x0 family.  The default depends upon how `as' was
     configured when it was built; normally, the default is to assemble
     code for the 68020 microprocessor.  The following options may be
     used to change the default.  These options control which
     instructions and addressing modes are permitted.  The members of
     the 680x0 family are very similar.  For detailed information about
     the differences, see the Motorola manuals.

    `-m68000'
    `-m68ec000'
    `-m68hc000'
    `-m68hc001'
    `-m68008'
    `-m68302'
    `-m68306'
    `-m68307'
    `-m68322'
    `-m68356'
          Assemble for the 68000. `-m68008', `-m68302', and so on are
          synonyms for `-m68000', since the chips are the same from the
          point of view of the assembler.

    `-m68010'
          Assemble for the 68010.

    `-m68020'
    `-m68ec020'
          Assemble for the 68020.  This is normally the default.

    `-m68030'
    `-m68ec030'
          Assemble for the 68030.

    `-m68040'
    `-m68ec040'
          Assemble for the 68040.

    `-m68060'
    `-m68ec060'
          Assemble for the 68060.

    `-mcpu32'
    `-m68330'
    `-m68331'
    `-m68332'
    `-m68333'
    `-m68334'
    `-m68336'
    `-m68340'
    `-m68341'
    `-m68349'
    `-m68360'
          Assemble for the CPU32 family of chips.

    `-m5200'

    `-m5202'

    `-m5204'

    `-m5206'

    `-m5206e'

    `-m521x'

    `-m5249'

    `-m528x'

    `-m5307'

    `-m5407'

    `-m547x'

    `-m548x'

    `-mcfv4'

    `-mcfv4e'
          Assemble for the ColdFire family of chips.

    `-m68881'
    `-m68882'
          Assemble 68881 floating point instructions.  This is the
          default for the 68020, 68030, and the CPU32.  The 68040 and
          68060 always support floating point instructions.

    `-mno-68881'
          Do not assemble 68881 floating point instructions.  This is
          the default for 68000 and the 68010.  The 68040 and 68060
          always support floating point instructions, even if this
          option is used.

    `-m68851'
          Assemble 68851 MMU instructions.  This is the default for the
          68020, 68030, and 68060.  The 68040 accepts a somewhat
          different set of MMU instructions; `-m68851' and `-m68040'
          should not be used together.

    `-mno-68851'
          Do not assemble 68851 MMU instructions.  This is the default
          for the 68000, 68010, and the CPU32.  The 68040 accepts a
          somewhat different set of MMU instructions.


File: as.info,  Node: M68K-Syntax,  Next: M68K-Moto-Syntax,  Prev: M68K-Opts,  Up: M68K-Dependent

8.18.2 Syntax
-------------

This syntax for the Motorola 680x0 was developed at MIT.

   The 680x0 version of `as' uses instructions names and syntax
compatible with the Sun assembler.  Intervening periods are ignored;
for example, `movl' is equivalent to `mov.l'.

   In the following table APC stands for any of the address registers
(`%a0' through `%a7'), the program counter (`%pc'), the zero-address
relative to the program counter (`%zpc'), a suppressed address register
(`%za0' through `%za7'), or it may be omitted entirely.  The use of
SIZE means one of `w' or `l', and it may be omitted, along with the
leading colon, unless a scale is also specified.  The use of SCALE
means one of `1', `2', `4', or `8', and it may always be omitted along
with the leading colon.

   The following addressing modes are understood:
"Immediate"
     `#NUMBER'

"Data Register"
     `%d0' through `%d7'

"Address Register"
     `%a0' through `%a7'
     `%a7' is also known as `%sp', i.e. the Stack Pointer.  `%a6' is
     also known as `%fp', the Frame Pointer.

"Address Register Indirect"
     `%a0@' through `%a7@'

"Address Register Postincrement"
     `%a0@+' through `%a7@+'

"Address Register Predecrement"
     `%a0@-' through `%a7@-'

"Indirect Plus Offset"
     `APC@(NUMBER)'

"Index"
     `APC@(NUMBER,REGISTER:SIZE:SCALE)'

     The NUMBER may be omitted.

"Postindex"
     `APC@(NUMBER)@(ONUMBER,REGISTER:SIZE:SCALE)'

     The ONUMBER or the REGISTER, but not both, may be omitted.

"Preindex"
     `APC@(NUMBER,REGISTER:SIZE:SCALE)@(ONUMBER)'

     The NUMBER may be omitted.  Omitting the REGISTER produces the
     Postindex addressing mode.

"Absolute"
     `SYMBOL', or `DIGITS', optionally followed by `:b', `:w', or `:l'.


File: as.info,  Node: M68K-Moto-Syntax,  Next: M68K-Float,  Prev: M68K-Syntax,  Up: M68K-Dependent

8.18.3 Motorola Syntax
----------------------

The standard Motorola syntax for this chip differs from the syntax
already discussed (*note Syntax: M68K-Syntax.).  `as' can accept
Motorola syntax for operands, even if MIT syntax is used for other
operands in the same instruction.  The two kinds of syntax are fully
compatible.

   In the following table APC stands for any of the address registers
(`%a0' through `%a7'), the program counter (`%pc'), the zero-address
relative to the program counter (`%zpc'), or a suppressed address
register (`%za0' through `%za7').  The use of SIZE means one of `w' or
`l', and it may always be omitted along with the leading dot.  The use
of SCALE means one of `1', `2', `4', or `8', and it may always be
omitted along with the leading asterisk.

   The following additional addressing modes are understood:

"Address Register Indirect"
     `(%a0)' through `(%a7)'
     `%a7' is also known as `%sp', i.e. the Stack Pointer.  `%a6' is
     also known as `%fp', the Frame Pointer.

"Address Register Postincrement"
     `(%a0)+' through `(%a7)+'

"Address Register Predecrement"
     `-(%a0)' through `-(%a7)'

"Indirect Plus Offset"
     `NUMBER(%A0)' through `NUMBER(%A7)', or `NUMBER(%PC)'.

     The NUMBER may also appear within the parentheses, as in
     `(NUMBER,%A0)'.  When used with the PC, the NUMBER may be omitted
     (with an address register, omitting the NUMBER produces Address
     Register Indirect mode).

"Index"
     `NUMBER(APC,REGISTER.SIZE*SCALE)'

     The NUMBER may be omitted, or it may appear within the
     parentheses.  The APC may be omitted.  The REGISTER and the APC
     may appear in either order.  If both APC and REGISTER are address
     registers, and the SIZE and SCALE are omitted, then the first
     register is taken as the base register, and the second as the
     index register.

"Postindex"
     `([NUMBER,APC],REGISTER.SIZE*SCALE,ONUMBER)'

     The ONUMBER, or the REGISTER, or both, may be omitted.  Either the
     NUMBER or the APC may be omitted, but not both.

"Preindex"
     `([NUMBER,APC,REGISTER.SIZE*SCALE],ONUMBER)'

     The NUMBER, or the APC, or the REGISTER, or any two of them, may
     be omitted.  The ONUMBER may be omitted.  The REGISTER and the APC
     may appear in either order.  If both APC and REGISTER are address
     registers, and the SIZE and SCALE are omitted, then the first
     register is taken as the base register, and the second as the
     index register.


File: as.info,  Node: M68K-Float,  Next: M68K-Directives,  Prev: M68K-Moto-Syntax,  Up: M68K-Dependent

8.18.4 Floating Point
---------------------

Packed decimal (P) format floating literals are not supported.  Feel
free to add the code!

   The floating point formats generated by directives are these.

`.float'
     `Single' precision floating point constants.

`.double'
     `Double' precision floating point constants.

`.extend'
`.ldouble'
     `Extended' precision (`long double') floating point constants.


File: as.info,  Node: M68K-Directives,  Next: M68K-opcodes,  Prev: M68K-Float,  Up: M68K-Dependent

8.18.5 680x0 Machine Directives
-------------------------------

In order to be compatible with the Sun assembler the 680x0 assembler
understands the following directives.

`.data1'
     This directive is identical to a `.data 1' directive.

`.data2'
     This directive is identical to a `.data 2' directive.

`.even'
     This directive is a special case of the `.align' directive; it
     aligns the output to an even byte boundary.

`.skip'
     This directive is identical to a `.space' directive.

`.arch NAME'
     Select the target architecture and extension features.  Valid
     valuse for NAME are the same as for the `-march' command line
     option.  This directive cannot be specified after any instructions
     have been assembled.  If it is given multiple times, or in
     conjuction with the `-march' option, all uses must be for the same
     architecture and extension set.

`.cpu NAME'
     Select the target cpu.  Valid valuse for NAME are the same as for
     the `-mcpu' command line option.  This directive cannot be
     specified after any instructions have been assembled.  If it is
     given multiple times, or in conjuction with the `-mopt' option,
     all uses must be for the same cpu.



File: as.info,  Node: M68K-opcodes,  Prev: M68K-Directives,  Up: M68K-Dependent

8.18.6 Opcodes
--------------

* Menu:

* M68K-Branch::                 Branch Improvement
* M68K-Chars::                  Special Characters


File: as.info,  Node: M68K-Branch,  Next: M68K-Chars,  Up: M68K-opcodes

8.18.6.1 Branch Improvement
...........................

Certain pseudo opcodes are permitted for branch instructions.  They
expand to the shortest branch instruction that reach the target.
Generally these mnemonics are made by substituting `j' for `b' at the
start of a Motorola mnemonic.

   The following table summarizes the pseudo-operations.  A `*' flags
cases that are more fully described after the table:

               Displacement
               +------------------------------------------------------------
               |                68020           68000/10, not PC-relative OK
     Pseudo-Op |BYTE    WORD    LONG            ABSOLUTE LONG JUMP    **
               +------------------------------------------------------------
          jbsr |bsrs    bsrw    bsrl            jsr
           jra |bras    braw    bral            jmp
     *     jXX |bXXs    bXXw    bXXl            bNXs;jmp
     *    dbXX | N/A    dbXXw   dbXX;bras;bral  dbXX;bras;jmp
          fjXX | N/A    fbXXw   fbXXl            N/A

     XX: condition
     NX: negative of condition XX
                       `*'--see full description below
         `**'--this expansion mode is disallowed by `--pcrel'

`jbsr'
`jra'
     These are the simplest jump pseudo-operations; they always map to
     one particular machine instruction, depending on the displacement
     to the branch target.  This instruction will be a byte or word
     branch is that is sufficient.  Otherwise, a long branch will be
     emitted if available.  If no long branches are available and the
     `--pcrel' option is not given, an absolute long jump will be
     emitted instead.  If no long branches are available, the `--pcrel'
     option is given, and a word branch cannot reach the target, an
     error message is generated.

     In addition to standard branch operands, `as' allows these
     pseudo-operations to have all operands that are allowed for jsr
     and jmp, substituting these instructions if the operand given is
     not valid for a branch instruction.

`jXX'
     Here, `jXX' stands for an entire family of pseudo-operations,
     where XX is a conditional branch or condition-code test.  The full
     list of pseudo-ops in this family is:
           jhi   jls   jcc   jcs   jne   jeq   jvc
           jvs   jpl   jmi   jge   jlt   jgt   jle

     Usually, each of these pseudo-operations expands to a single branch
     instruction.  However, if a word branch is not sufficient, no long
     branches are available, and the `--pcrel' option is not given, `as'
     issues a longer code fragment in terms of NX, the opposite
     condition to XX.  For example, under these conditions:
              jXX foo
     gives
               bNXs oof
               jmp foo
           oof:

`dbXX'
     The full family of pseudo-operations covered here is
           dbhi   dbls   dbcc   dbcs   dbne   dbeq   dbvc
           dbvs   dbpl   dbmi   dbge   dblt   dbgt   dble
           dbf    dbra   dbt

     Motorola `dbXX' instructions allow word displacements only.  When
     a word displacement is sufficient, each of these pseudo-operations
     expands to the corresponding Motorola instruction.  When a word
     displacement is not sufficient and long branches are available,
     when the source reads `dbXX foo', `as' emits
               dbXX oo1
               bras oo2
           oo1:bral foo
           oo2:

     If, however, long branches are not available and the `--pcrel'
     option is not given, `as' emits
               dbXX oo1
               bras oo2
           oo1:jmp foo
           oo2:

`fjXX'
     This family includes
           fjne   fjeq   fjge   fjlt   fjgt   fjle   fjf
           fjt    fjgl   fjgle  fjnge  fjngl  fjngle fjngt
           fjnle  fjnlt  fjoge  fjogl  fjogt  fjole  fjolt
           fjor   fjseq  fjsf   fjsne  fjst   fjueq  fjuge
           fjugt  fjule  fjult  fjun

     Each of these pseudo-operations always expands to a single Motorola
     coprocessor branch instruction, word or long.  All Motorola
     coprocessor branch instructions allow both word and long
     displacements.



File: as.info,  Node: M68K-Chars,  Prev: M68K-Branch,  Up: M68K-opcodes

8.18.6.2 Special Characters
...........................

The immediate character is `#' for Sun compatibility.  The line-comment
character is `|' (unless the `--bitwise-or' option is used).  If a `#'
appears at the beginning of a line, it is treated as a comment unless
it looks like `# line file', in which case it is treated normally.


File: as.info,  Node: M68HC11-Dependent,  Next: MIPS-Dependent,  Prev: M68K-Dependent,  Up: Machine Dependencies

8.19 M68HC11 and M68HC12 Dependent Features
===========================================

* Menu:

* M68HC11-Opts::                   M68HC11 and M68HC12 Options
* M68HC11-Syntax::                 Syntax
* M68HC11-Modifiers::              Symbolic Operand Modifiers
* M68HC11-Directives::             Assembler Directives
* M68HC11-Float::                  Floating Point
* M68HC11-opcodes::                Opcodes


File: as.info,  Node: M68HC11-Opts,  Next: M68HC11-Syntax,  Up: M68HC11-Dependent

8.19.1 M68HC11 and M68HC12 Options
----------------------------------

The Motorola 68HC11 and 68HC12 version of `as' have a few machine
dependent options.

`-m68hc11'
     This option switches the assembler in the M68HC11 mode. In this
     mode, the assembler only accepts 68HC11 operands and mnemonics. It
     produces code for the 68HC11.

`-m68hc12'
     This option switches the assembler in the M68HC12 mode. In this
     mode, the assembler also accepts 68HC12 operands and mnemonics. It
     produces code for the 68HC12. A few 68HC11 instructions are
     replaced by some 68HC12 instructions as recommended by Motorola
     specifications.

`-m68hcs12'
     This option switches the assembler in the M68HCS12 mode.  This
     mode is similar to `-m68hc12' but specifies to assemble for the
     68HCS12 series.  The only difference is on the assembling of the
     `movb' and `movw' instruction when a PC-relative operand is used.

`-mshort'
     This option controls the ABI and indicates to use a 16-bit integer
     ABI.  It has no effect on the assembled instructions.  This is the
     default.

`-mlong'
     This option controls the ABI and indicates to use a 32-bit integer
     ABI.

`-mshort-double'
     This option controls the ABI and indicates to use a 32-bit float
     ABI.  This is the default.

`-mlong-double'
     This option controls the ABI and indicates to use a 64-bit float
     ABI.

`--strict-direct-mode'
     You can use the `--strict-direct-mode' option to disable the
     automatic translation of direct page mode addressing into extended
     mode when the instruction does not support direct mode.  For
     example, the `clr' instruction does not support direct page mode
     addressing. When it is used with the direct page mode, `as' will
     ignore it and generate an absolute addressing.  This option
     prevents `as' from doing this, and the wrong usage of the direct
     page mode will raise an error.

`--short-branchs'
     The `--short-branchs' option turns off the translation of relative
     branches into absolute branches when the branch offset is out of
     range. By default `as' transforms the relative branch (`bsr',
     `bgt', `bge', `beq', `bne', `ble', `blt', `bhi', `bcc', `bls',
     `bcs', `bmi', `bvs', `bvs', `bra') into an absolute branch when
     the offset is out of the -128 .. 127 range.  In that case, the
     `bsr' instruction is translated into a `jsr', the `bra'
     instruction is translated into a `jmp' and the conditional branchs
     instructions are inverted and followed by a `jmp'. This option
     disables these translations and `as' will generate an error if a
     relative branch is out of range. This option does not affect the
     optimization associated to the `jbra', `jbsr' and `jbXX' pseudo
     opcodes.

`--force-long-branchs'
     The `--force-long-branchs' option forces the translation of
     relative branches into absolute branches. This option does not
     affect the optimization associated to the `jbra', `jbsr' and
     `jbXX' pseudo opcodes.

`--print-insn-syntax'
     You can use the `--print-insn-syntax' option to obtain the syntax
     description of the instruction when an error is detected.

`--print-opcodes'
     The `--print-opcodes' option prints the list of all the
     instructions with their syntax. The first item of each line
     represents the instruction name and the rest of the line indicates
     the possible operands for that instruction. The list is printed in
     alphabetical order. Once the list is printed `as' exits.

`--generate-example'
     The `--generate-example' option is similar to `--print-opcodes'
     but it generates an example for each instruction instead.


File: as.info,  Node: M68HC11-Syntax,  Next: M68HC11-Modifiers,  Prev: M68HC11-Opts,  Up: M68HC11-Dependent

8.19.2 Syntax
-------------

In the M68HC11 syntax, the instruction name comes first and it may be
followed by one or several operands (up to three). Operands are
separated by comma (`,'). In the normal mode, `as' will complain if too
many operands are specified for a given instruction. In the MRI mode
(turned on with `-M' option), it will treat them as comments. Example:

     inx
     lda  #23
     bset 2,x #4
     brclr *bot #8 foo

   The following addressing modes are understood for 68HC11 and 68HC12:
"Immediate"
     `#NUMBER'

"Address Register"
     `NUMBER,X', `NUMBER,Y'

     The NUMBER may be omitted in which case 0 is assumed.

"Direct Addressing mode"
     `*SYMBOL', or `*DIGITS'

"Absolute"
     `SYMBOL', or `DIGITS'

   The M68HC12 has other more complex addressing modes. All of them are
supported and they are represented below:

"Constant Offset Indexed Addressing Mode"
     `NUMBER,REG'

     The NUMBER may be omitted in which case 0 is assumed.  The
     register can be either `X', `Y', `SP' or `PC'.  The assembler will
     use the smaller post-byte definition according to the constant
     value (5-bit constant offset, 9-bit constant offset or 16-bit
     constant offset).  If the constant is not known by the assembler
     it will use the 16-bit constant offset post-byte and the value
     will be resolved at link time.

"Offset Indexed Indirect"
     `[NUMBER,REG]'

     The register can be either `X', `Y', `SP' or `PC'.

"Auto Pre-Increment/Pre-Decrement/Post-Increment/Post-Decrement"
     `NUMBER,-REG' `NUMBER,+REG' `NUMBER,REG-' `NUMBER,REG+'

     The number must be in the range `-8'..`+8' and must not be 0.  The
     register can be either `X', `Y', `SP' or `PC'.

"Accumulator Offset"
     `ACC,REG'

     The accumulator register can be either `A', `B' or `D'.  The
     register can be either `X', `Y', `SP' or `PC'.

"Accumulator D offset indexed-indirect"
     `[D,REG]'

     The register can be either `X', `Y', `SP' or `PC'.


   For example:

     ldab 1024,sp
     ldd [10,x]
     orab 3,+x
     stab -2,y-
     ldx a,pc
     sty [d,sp]


File: as.info,  Node: M68HC11-Modifiers,  Next: M68HC11-Directives,  Prev: M68HC11-Syntax,  Up: M68HC11-Dependent

8.19.3 Symbolic Operand Modifiers
---------------------------------

The assembler supports several modifiers when using symbol addresses in
68HC11 and 68HC12 instruction operands.  The general syntax is the
following:

     %modifier(symbol)

`%addr'
     This modifier indicates to the assembler and linker to use the
     16-bit physical address corresponding to the symbol.  This is
     intended to be used on memory window systems to map a symbol in
     the memory bank window.  If the symbol is in a memory expansion
     part, the physical address corresponds to the symbol address
     within the memory bank window.  If the symbol is not in a memory
     expansion part, this is the symbol address (using or not using the
     %addr modifier has no effect in that case).

`%page'
     This modifier indicates to use the memory page number corresponding
     to the symbol.  If the symbol is in a memory expansion part, its
     page number is computed by the linker as a number used to map the
     page containing the symbol in the memory bank window.  If the
     symbol is not in a memory expansion part, the page number is 0.

`%hi'
     This modifier indicates to use the 8-bit high part of the physical
     address of the symbol.

`%lo'
     This modifier indicates to use the 8-bit low part of the physical
     address of the symbol.


   For example a 68HC12 call to a function `foo_example' stored in
memory expansion part could be written as follows:

     call %addr(foo_example),%page(foo_example)

   and this is equivalent to

     call foo_example

   And for 68HC11 it could be written as follows:

     ldab #%page(foo_example)
     stab _page_switch
     jsr  %addr(foo_example)


File: as.info,  Node: M68HC11-Directives,  Next: M68HC11-Float,  Prev: M68HC11-Modifiers,  Up: M68HC11-Dependent

8.19.4 Assembler Directives
---------------------------

The 68HC11 and 68HC12 version of `as' have the following specific
assembler directives:

`.relax'
     The relax directive is used by the `GNU Compiler' to emit a
     specific relocation to mark a group of instructions for linker
     relaxation.  The sequence of instructions within the group must be
     known to the linker so that relaxation can be performed.

`.mode [mshort|mlong|mshort-double|mlong-double]'
     This directive specifies the ABI.  It overrides the `-mshort',
     `-mlong', `-mshort-double' and `-mlong-double' options.

`.far SYMBOL'
     This directive marks the symbol as a `far' symbol meaning that it
     uses a `call/rtc' calling convention as opposed to `jsr/rts'.
     During a final link, the linker will identify references to the
     `far' symbol and will verify the proper calling convention.

`.interrupt SYMBOL'
     This directive marks the symbol as an interrupt entry point.  This
     information is then used by the debugger to correctly unwind the
     frame across interrupts.

`.xrefb SYMBOL'
     This directive is defined for compatibility with the
     `Specification for Motorola 8 and 16-Bit Assembly Language Input
     Standard' and is ignored.



File: as.info,  Node: M68HC11-Float,  Next: M68HC11-opcodes,  Prev: M68HC11-Directives,  Up: M68HC11-Dependent

8.19.5 Floating Point
---------------------

Packed decimal (P) format floating literals are not supported.  Feel
free to add the code!

   The floating point formats generated by directives are these.

`.float'
     `Single' precision floating point constants.

`.double'
     `Double' precision floating point constants.

`.extend'
`.ldouble'
     `Extended' precision (`long double') floating point constants.


File: as.info,  Node: M68HC11-opcodes,  Prev: M68HC11-Float,  Up: M68HC11-Dependent

8.19.6 Opcodes
--------------

* Menu:

* M68HC11-Branch::                 Branch Improvement


File: as.info,  Node: M68HC11-Branch,  Up: M68HC11-opcodes

8.19.6.1 Branch Improvement
...........................

Certain pseudo opcodes are permitted for branch instructions.  They
expand to the shortest branch instruction that reach the target.
Generally these mnemonics are made by prepending `j' to the start of
Motorola mnemonic. These pseudo opcodes are not affected by the
`--short-branchs' or `--force-long-branchs' options.

   The following table summarizes the pseudo-operations.

                             Displacement Width
          +-------------------------------------------------------------+
          |                     Options                                 |
          |    --short-branchs            --force-long-branchs          |
          +--------------------------+----------------------------------+
       Op |BYTE             WORD     | BYTE          WORD               |
          +--------------------------+----------------------------------+
      bsr | bsr <pc-rel>    <error>  |               jsr <abs>          |
      bra | bra <pc-rel>    <error>  |               jmp <abs>          |
     jbsr | bsr <pc-rel>   jsr <abs> | bsr <pc-rel>  jsr <abs>          |
     jbra | bra <pc-rel>   jmp <abs> | bra <pc-rel>  jmp <abs>          |
      bXX | bXX <pc-rel>    <error>  |               bNX +3; jmp <abs>  |
     jbXX | bXX <pc-rel>   bNX +3;   | bXX <pc-rel>  bNX +3; jmp <abs>  |
          |                jmp <abs> |                                  |
          +--------------------------+----------------------------------+
     XX: condition
     NX: negative of condition XX

`jbsr'
`jbra'
     These are the simplest jump pseudo-operations; they always map to
     one particular machine instruction, depending on the displacement
     to the branch target.

`jbXX'
     Here, `jbXX' stands for an entire family of pseudo-operations,
     where XX is a conditional branch or condition-code test.  The full
     list of pseudo-ops in this family is:
           jbcc   jbeq   jbge   jbgt   jbhi   jbvs   jbpl  jblo
           jbcs   jbne   jblt   jble   jbls   jbvc   jbmi

     For the cases of non-PC relative displacements and long
     displacements, `as' issues a longer code fragment in terms of NX,
     the opposite condition to XX.  For example, for the non-PC
     relative case:
              jbXX foo
     gives
               bNXs oof
               jmp foo
           oof:



File: as.info,  Node: MIPS-Dependent,  Next: MMIX-Dependent,  Prev: M68HC11-Dependent,  Up: Machine Dependencies

8.20 MIPS Dependent Features
============================

   GNU `as' for MIPS architectures supports several different MIPS
processors, and MIPS ISA levels I through V, MIPS32, and MIPS64.  For
information about the MIPS instruction set, see `MIPS RISC
Architecture', by Kane and Heindrich (Prentice-Hall).  For an overview
of MIPS assembly conventions, see "Appendix D: Assembly Language
Programming" in the same work.

* Menu:

* MIPS Opts::   	Assembler options
* MIPS Object:: 	ECOFF object code
* MIPS Stabs::  	Directives for debugging information
* MIPS ISA::    	Directives to override the ISA level
* MIPS symbol sizes::   Directives to override the size of symbols
* MIPS autoextend::	Directives for extending MIPS 16 bit instructions
* MIPS insn::		Directive to mark data as an instruction
* MIPS option stack::	Directives to save and restore options
* MIPS ASE instruction generation overrides:: Directives to control
  			generation of MIPS ASE instructions


File: as.info,  Node: MIPS Opts,  Next: MIPS Object,  Up: MIPS-Dependent

8.20.1 Assembler options
------------------------

The MIPS configurations of GNU `as' support these special options:

`-G NUM'
     This option sets the largest size of an object that can be
     referenced implicitly with the `gp' register.  It is only accepted
     for targets that use ECOFF format.  The default value is 8.

`-EB'
`-EL'
     Any MIPS configuration of `as' can select big-endian or
     little-endian output at run time (unlike the other GNU development
     tools, which must be configured for one or the other).  Use `-EB'
     to select big-endian output, and `-EL' for little-endian.

`-mips1'
`-mips2'
`-mips3'
`-mips4'
`-mips5'
`-mips32'
`-mips32r2'
`-mips64'
`-mips64r2'
     Generate code for a particular MIPS Instruction Set Architecture
     level.  `-mips1' corresponds to the R2000 and R3000 processors,
     `-mips2' to the R6000 processor, `-mips3' to the R4000 processor,
     and `-mips4' to the R8000 and R10000 processors.  `-mips5',
     `-mips32', `-mips32r2', `-mips64', and `-mips64r2' correspond to
     generic MIPS V, MIPS32, MIPS32 RELEASE 2, MIPS64, and MIPS64
     RELEASE 2 ISA processors, respectively.  You can also switch
     instruction sets during the assembly; see *Note Directives to
     override the ISA level: MIPS ISA.

`-mgp32'
`-mfp32'
     Some macros have different expansions for 32-bit and 64-bit
     registers.  The register sizes are normally inferred from the ISA
     and ABI, but these flags force a certain group of registers to be
     treated as 32 bits wide at all times.  `-mgp32' controls the size
     of general-purpose registers and `-mfp32' controls the size of
     floating-point registers.

     On some MIPS variants there is a 32-bit mode flag; when this flag
     is set, 64-bit instructions generate a trap.  Also, some 32-bit
     OSes only save the 32-bit registers on a context switch, so it is
     essential never to use the 64-bit registers.

`-mgp64'
     Assume that 64-bit general purpose registers are available.  This
     is provided in the interests of symmetry with -gp32.

`-mips16'
`-no-mips16'
     Generate code for the MIPS 16 processor.  This is equivalent to
     putting `.set mips16' at the start of the assembly file.
     `-no-mips16' turns off this option.

`-mips3d'
`-no-mips3d'
     Generate code for the MIPS-3D Application Specific Extension.
     This tells the assembler to accept MIPS-3D instructions.
     `-no-mips3d' turns off this option.

`-mdmx'
`-no-mdmx'
     Generate code for the MDMX Application Specific Extension.  This
     tells the assembler to accept MDMX instructions.  `-no-mdmx' turns
     off this option.

`-mdsp'
`-mno-dsp'
     Generate code for the DSP Application Specific Extension.  This
     tells the assembler to accept DSP instructions.  `-mno-dsp' turns
     off this option.

`-mmt'
`-mno-mt'
     Generate code for the MT Application Specific Extension.  This
     tells the assembler to accept MT instructions.  `-mno-mt' turns
     off this option.

`-mfix7000'
`-mno-fix7000'
     Cause nops to be inserted if the read of the destination register
     of an mfhi or mflo instruction occurs in the following two
     instructions.

`-mfix-vr4120'
`-no-mfix-vr4120'
     Insert nops to work around certain VR4120 errata.  This option is
     intended to be used on GCC-generated code: it is not designed to
     catch all problems in hand-written assembler code.

`-mfix-vr4130'
`-no-mfix-vr4130'
     Insert nops to work around the VR4130 `mflo'/`mfhi' errata.

`-m4010'
`-no-m4010'
     Generate code for the LSI R4010 chip.  This tells the assembler to
     accept the R4010 specific instructions (`addciu', `ffc', etc.),
     and to not schedule `nop' instructions around accesses to the `HI'
     and `LO' registers.  `-no-m4010' turns off this option.

`-m4650'
`-no-m4650'
     Generate code for the MIPS R4650 chip.  This tells the assembler
     to accept the `mad' and `madu' instruction, and to not schedule
     `nop' instructions around accesses to the `HI' and `LO' registers.
     `-no-m4650' turns off this option.

`-m3900'
`-no-m3900'
`-m4100'
`-no-m4100'
     For each option `-mNNNN', generate code for the MIPS RNNNN chip.
     This tells the assembler to accept instructions specific to that
     chip, and to schedule for that chip's hazards.

`-march=CPU'
     Generate code for a particular MIPS cpu.  It is exactly equivalent
     to `-mCPU', except that there are more value of CPU understood.
     Valid CPU value are:

          2000, 3000, 3900, 4000, 4010, 4100, 4111, vr4120, vr4130,
          vr4181, 4300, 4400, 4600, 4650, 5000, rm5200, rm5230, rm5231,
          rm5261, rm5721, vr5400, vr5500, 6000, rm7000, 8000, rm9000,
          10000, 12000, mips32-4k, sb1

`-mtune=CPU'
     Schedule and tune for a particular MIPS cpu.  Valid CPU values are
     identical to `-march=CPU'.

`-mabi=ABI'
     Record which ABI the source code uses.  The recognized arguments
     are: `32', `n32', `o64', `64' and `eabi'.

`-msym32'
`-mno-sym32'
     Equivalent to adding `.set sym32' or `.set nosym32' to the
     beginning of the assembler input.  *Note MIPS symbol sizes::.

`-nocpp'
     This option is ignored.  It is accepted for command-line
     compatibility with other assemblers, which use it to turn off C
     style preprocessing.  With GNU `as', there is no need for
     `-nocpp', because the GNU assembler itself never runs the C
     preprocessor.

`--construct-floats'
`--no-construct-floats'
     The `--no-construct-floats' option disables the construction of
     double width floating point constants by loading the two halves of
     the value into the two single width floating point registers that
     make up the double width register.  This feature is useful if the
     processor support the FR bit in its status  register, and this bit
     is known (by the programmer) to be set.  This bit prevents the
     aliasing of the double width register by the single width
     registers.

     By default `--construct-floats' is selected, allowing construction
     of these floating point constants.

`--trap'
`--no-break'
     `as' automatically macro expands certain division and
     multiplication instructions to check for overflow and division by
     zero.  This option causes `as' to generate code to take a trap
     exception rather than a break exception when an error is detected.
     The trap instructions are only supported at Instruction Set
     Architecture level 2 and higher.

`--break'
`--no-trap'
     Generate code to take a break exception rather than a trap
     exception when an error is detected.  This is the default.

`-mpdr'
`-mno-pdr'
     Control generation of `.pdr' sections.  Off by default on IRIX, on
     elsewhere.

`-mshared'
`-mno-shared'
     When generating code using the Unix calling conventions (selected
     by `-KPIC' or `-mcall_shared'), gas will normally generate code
     which can go into a shared library.  The `-mno-shared' option
     tells gas to generate code which uses the calling convention, but
     can not go into a shared library.  The resulting code is slightly
     more efficient.  This option only affects the handling of the
     `.cpload' and `.cpsetup' pseudo-ops.


File: as.info,  Node: MIPS Object,  Next: MIPS Stabs,  Prev: MIPS Opts,  Up: MIPS-Dependent

8.20.2 MIPS ECOFF object code
-----------------------------

Assembling for a MIPS ECOFF target supports some additional sections
besides the usual `.text', `.data' and `.bss'.  The additional sections
are `.rdata', used for read-only data, `.sdata', used for small data,
and `.sbss', used for small common objects.

   When assembling for ECOFF, the assembler uses the `$gp' (`$28')
register to form the address of a "small object".  Any object in the
`.sdata' or `.sbss' sections is considered "small" in this sense.  For
external objects, or for objects in the `.bss' section, you can use the
`gcc' `-G' option to control the size of objects addressed via `$gp';
the default value is 8, meaning that a reference to any object eight
bytes or smaller uses `$gp'.  Passing `-G 0' to `as' prevents it from
using the `$gp' register on the basis of object size (but the assembler
uses `$gp' for objects in `.sdata' or `sbss' in any case).  The size of
an object in the `.bss' section is set by the `.comm' or `.lcomm'
directive that defines it.  The size of an external object may be set
with the `.extern' directive.  For example, `.extern sym,4' declares
that the object at `sym' is 4 bytes in length, whie leaving `sym'
otherwise undefined.

   Using small ECOFF objects requires linker support, and assumes that
the `$gp' register is correctly initialized (normally done
automatically by the startup code).  MIPS ECOFF assembly code must not
modify the `$gp' register.


File: as.info,  Node: MIPS Stabs,  Next: MIPS ISA,  Prev: MIPS Object,  Up: MIPS-Dependent

8.20.3 Directives for debugging information
-------------------------------------------

MIPS ECOFF `as' supports several directives used for generating
debugging information which are not support by traditional MIPS
assemblers.  These are `.def', `.endef', `.dim', `.file', `.scl',
`.size', `.tag', `.type', `.val', `.stabd', `.stabn', and `.stabs'.
The debugging information generated by the three `.stab' directives can
only be read by GDB, not by traditional MIPS debuggers (this
enhancement is required to fully support C++ debugging).  These
directives are primarily used by compilers, not assembly language
programmers!


File: as.info,  Node: MIPS symbol sizes,  Next: MIPS autoextend,  Prev: MIPS ISA,  Up: MIPS-Dependent

8.20.4 Directives to override the size of symbols
-------------------------------------------------

The n64 ABI allows symbols to have any 64-bit value.  Although this
provides a great deal of flexibility, it means that some macros have
much longer expansions than their 32-bit counterparts.  For example,
the non-PIC expansion of `dla $4,sym' is usually:

     lui     $4,%highest(sym)
     lui     $1,%hi(sym)
     daddiu  $4,$4,%higher(sym)
     daddiu  $1,$1,%lo(sym)
     dsll32  $4,$4,0
     daddu   $4,$4,$1

   whereas the 32-bit expansion is simply:

     lui     $4,%hi(sym)
     daddiu  $4,$4,%lo(sym)

   n64 code is sometimes constructed in such a way that all symbolic
constants are known to have 32-bit values, and in such cases, it's
preferable to use the 32-bit expansion instead of the 64-bit expansion.

   You can use the `.set sym32' directive to tell the assembler that,
from this point on, all expressions of the form `SYMBOL' or `SYMBOL +
OFFSET' have 32-bit values.  For example:

     .set sym32
     dla     $4,sym
     lw      $4,sym+16
     sw      $4,sym+0x8000($4)

   will cause the assembler to treat `sym', `sym+16' and `sym+0x8000'
as 32-bit values.  The handling of non-symbolic addresses is not
affected.

   The directive `.set nosym32' ends a `.set sym32' block and reverts
to the normal behavior.  It is also possible to change the symbol size
using the command-line options `-msym32' and `-mno-sym32'.

   These options and directives are always accepted, but at present,
they have no effect for anything other than n64.


File: as.info,  Node: MIPS ISA,  Next: MIPS symbol sizes,  Prev: MIPS Stabs,  Up: MIPS-Dependent

8.20.5 Directives to override the ISA level
-------------------------------------------

GNU `as' supports an additional directive to change the MIPS
Instruction Set Architecture level on the fly: `.set mipsN'.  N should
be a number from 0 to 5, or 32, 32r2, 64 or 64r2.  The values other
than 0 make the assembler accept instructions for the corresponding ISA
level, from that point on in the assembly.  `.set mipsN' affects not
only which instructions are permitted, but also how certain macros are
expanded.  `.set mips0' restores the ISA level to its original level:
either the level you selected with command line options, or the default
for your configuration.  You can use this feature to permit specific
R4000 instructions while assembling in 32 bit mode.  Use this directive
with care!

   The directive `.set mips16' puts the assembler into MIPS 16 mode, in
which it will assemble instructions for the MIPS 16 processor.  Use
`.set nomips16' to return to normal 32 bit mode.

   Traditional MIPS assemblers do not support this directive.


File: as.info,  Node: MIPS autoextend,  Next: MIPS insn,  Prev: MIPS symbol sizes,  Up: MIPS-Dependent

8.20.6 Directives for extending MIPS 16 bit instructions
--------------------------------------------------------

By default, MIPS 16 instructions are automatically extended to 32 bits
when necessary.  The directive `.set noautoextend' will turn this off.
When `.set noautoextend' is in effect, any 32 bit instruction must be
explicitly extended with the `.e' modifier (e.g., `li.e $4,1000').  The
directive `.set autoextend' may be used to once again automatically
extend instructions when necessary.

   This directive is only meaningful when in MIPS 16 mode.  Traditional
MIPS assemblers do not support this directive.


File: as.info,  Node: MIPS insn,  Next: MIPS option stack,  Prev: MIPS autoextend,  Up: MIPS-Dependent

8.20.7 Directive to mark data as an instruction
-----------------------------------------------

The `.insn' directive tells `as' that the following data is actually
instructions.  This makes a difference in MIPS 16 mode: when loading
the address of a label which precedes instructions, `as' automatically
adds 1 to the value, so that jumping to the loaded address will do the
right thing.


File: as.info,  Node: MIPS option stack,  Next: MIPS ASE instruction generation overrides,  Prev: MIPS insn,  Up: MIPS-Dependent

8.20.8 Directives to save and restore options
---------------------------------------------

The directives `.set push' and `.set pop' may be used to save and
restore the current settings for all the options which are controlled
by `.set'.  The `.set push' directive saves the current settings on a
stack.  The `.set pop' directive pops the stack and restores the
settings.

   These directives can be useful inside an macro which must change an
option such as the ISA level or instruction reordering but does not want
to change the state of the code which invoked the macro.

   Traditional MIPS assemblers do not support these directives.


File: as.info,  Node: MIPS ASE instruction generation overrides,  Prev: MIPS option stack,  Up: MIPS-Dependent

8.20.9 Directives to control generation of MIPS ASE instructions
----------------------------------------------------------------

The directive `.set mips3d' makes the assembler accept instructions
from the MIPS-3D Application Specific Extension from that point on in
the assembly.  The `.set nomips3d' directive prevents MIPS-3D
instructions from being accepted.

   The directive `.set mdmx' makes the assembler accept instructions
from the MDMX Application Specific Extension from that point on in the
assembly.  The `.set nomdmx' directive prevents MDMX instructions from
being accepted.

   The directive `.set dsp' makes the assembler accept instructions
from the DSP Application Specific Extension from that point on in the
assembly.  The `.set nodsp' directive prevents DSP instructions from
being accepted.

   The directive `.set mt' makes the assembler accept instructions from
the MT Application Specific Extension from that point on in the
assembly.  The `.set nomt' directive prevents MT instructions from
being accepted.

   Traditional MIPS assemblers do not support these directives.


File: as.info,  Node: MMIX-Dependent,  Next: MSP430-Dependent,  Prev: MIPS-Dependent,  Up: Machine Dependencies

8.21 MMIX Dependent Features
============================

* Menu:

* MMIX-Opts::              Command-line Options
* MMIX-Expand::            Instruction expansion
* MMIX-Syntax::            Syntax
* MMIX-mmixal::		   Differences to `mmixal' syntax and semantics


File: as.info,  Node: MMIX-Opts,  Next: MMIX-Expand,  Up: MMIX-Dependent

8.21.1 Command-line Options
---------------------------

The MMIX version of `as' has some machine-dependent options.

   When `--fixed-special-register-names' is specified, only the register
names specified in *Note MMIX-Regs:: are recognized in the instructions
`PUT' and `GET'.

   You can use the `--globalize-symbols' to make all symbols global.
This option is useful when splitting up a `mmixal' program into several
files.

   The `--gnu-syntax' turns off most syntax compatibility with
`mmixal'.  Its usability is currently doubtful.

   The `--relax' option is not fully supported, but will eventually make
the object file prepared for linker relaxation.

   If you want to avoid inadvertently calling a predefined symbol and
would rather get an error, for example when using `as' with a compiler
or other machine-generated code, specify `--no-predefined-syms'.  This
turns off built-in predefined definitions of all such symbols,
including rounding-mode symbols, segment symbols, `BIT' symbols, and
`TRAP' symbols used in `mmix' "system calls".  It also turns off
predefined special-register names, except when used in `PUT' and `GET'
instructions.

   By default, some instructions are expanded to fit the size of the
operand or an external symbol (*note MMIX-Expand::).  By passing
`--no-expand', no such expansion will be done, instead causing errors
at link time if the operand does not fit.

   The `mmixal' documentation (*note mmixsite::) specifies that global
registers allocated with the `GREG' directive (*note MMIX-greg::) and
initialized to the same non-zero value, will refer to the same global
register.  This isn't strictly enforceable in `as' since the final
addresses aren't known until link-time, but it will do an effort unless
the `--no-merge-gregs' option is specified.  (Register merging isn't
yet implemented in `ld'.)

   `as' will warn every time it expands an instruction to fit an
operand unless the option `-x' is specified.  It is believed that this
behaviour is more useful than just mimicking `mmixal''s behaviour, in
which instructions are only expanded if the `-x' option is specified,
and assembly fails otherwise, when an instruction needs to be expanded.
It needs to be kept in mind that `mmixal' is both an assembler and
linker, while `as' will expand instructions that at link stage can be
contracted.  (Though linker relaxation isn't yet implemented in `ld'.)
The option `-x' also imples `--linker-allocated-gregs'.

   If instruction expansion is enabled, `as' can expand a `PUSHJ'
instruction into a series of instructions.  The shortest expansion is
to not expand it, but just mark the call as redirectable to a stub,
which `ld' creates at link-time, but only if the original `PUSHJ'
instruction is found not to reach the target.  The stub consists of the
necessary instructions to form a jump to the target.  This happens if
`as' can assert that the `PUSHJ' instruction can reach such a stub.
The option `--no-pushj-stubs' disables this shorter expansion, and the
longer series of instructions is then created at assembly-time.  The
option `--no-stubs' is a synonym, intended for compatibility with
future releases, where generation of stubs for other instructions may
be implemented.

   Usually a two-operand-expression (*note GREG-base::) without a
matching `GREG' directive is treated as an error by `as'.  When the
option `--linker-allocated-gregs' is in effect, they are instead passed
through to the linker, which will allocate as many global registers as
is needed.


File: as.info,  Node: MMIX-Expand,  Next: MMIX-Syntax,  Prev: MMIX-Opts,  Up: MMIX-Dependent

8.21.2 Instruction expansion
----------------------------

When `as' encounters an instruction with an operand that is either not
known or does not fit the operand size of the instruction, `as' (and
`ld') will expand the instruction into a sequence of instructions
semantically equivalent to the operand fitting the instruction.
Expansion will take place for the following instructions:

`GETA'
     Expands to a sequence of four instructions: `SETL', `INCML',
     `INCMH' and `INCH'.  The operand must be a multiple of four.

Conditional branches
     A branch instruction is turned into a branch with the complemented
     condition and prediction bit over five instructions; four
     instructions setting `$255' to the operand value, which like with
     `GETA' must be a multiple of four, and a final `GO $255,$255,0'.

`PUSHJ'
     Similar to expansion for conditional branches; four instructions
     set `$255' to the operand value, followed by a `PUSHGO
     $255,$255,0'.

`JMP'
     Similar to conditional branches and `PUSHJ'.  The final instruction
     is `GO $255,$255,0'.

   The linker `ld' is expected to shrink these expansions for code
assembled with `--relax' (though not currently implemented).


File: as.info,  Node: MMIX-Syntax,  Next: MMIX-mmixal,  Prev: MMIX-Expand,  Up: MMIX-Dependent

8.21.3 Syntax
-------------

The assembly syntax is supposed to be upward compatible with that
described in Sections 1.3 and 1.4 of `The Art of Computer Programming,
Volume 1'.  Draft versions of those chapters as well as other MMIX
information is located at
`http://www-cs-faculty.stanford.edu/~knuth/mmix-news.html'.  Most code
examples from the mmixal package located there should work unmodified
when assembled and linked as single files, with a few noteworthy
exceptions (*note MMIX-mmixal::).

   Before an instruction is emitted, the current location is aligned to
the next four-byte boundary.  If a label is defined at the beginning of
the line, its value will be the aligned value.

   In addition to the traditional hex-prefix `0x', a hexadecimal number
can also be specified by the prefix character `#'.

   After all operands to an MMIX instruction or directive have been
specified, the rest of the line is ignored, treated as a comment.

* Menu:

* MMIX-Chars::		        Special Characters
* MMIX-Symbols::		Symbols
* MMIX-Regs::			Register Names
* MMIX-Pseudos::		Assembler Directives


File: as.info,  Node: MMIX-Chars,  Next: MMIX-Symbols,  Up: MMIX-Syntax

8.21.3.1 Special Characters
...........................

The characters `*' and `#' are line comment characters; each start a
comment at the beginning of a line, but only at the beginning of a
line.  A `#' prefixes a hexadecimal number if found elsewhere on a line.

   Two other characters, `%' and `!', each start a comment anywhere on
the line.  Thus you can't use the `modulus' and `not' operators in
expressions normally associated with these two characters.

   A `;' is a line separator, treated as a new-line, so separate
instructions can be specified on a single line.


File: as.info,  Node: MMIX-Symbols,  Next: MMIX-Regs,  Prev: MMIX-Chars,  Up: MMIX-Syntax

8.21.3.2 Symbols
................

The character `:' is permitted in identifiers.  There are two
exceptions to it being treated as any other symbol character: if a
symbol begins with `:', it means that the symbol is in the global
namespace and that the current prefix should not be prepended to that
symbol (*note MMIX-prefix::).  The `:' is then not considered part of
the symbol.  For a symbol in the label position (first on a line), a `:'
at the end of a symbol is silently stripped off.  A label is permitted,
but not required, to be followed by a `:', as with many other assembly
formats.

   The character `@' in an expression, is a synonym for `.', the
current location.

   In addition to the common forward and backward local symbol formats
(*note Symbol Names::), they can be specified with upper-case `B' and
`F', as in `8B' and `9F'.  A local label defined for the current
position is written with a `H' appended to the number:
     3H LDB $0,$1,2
   This and traditional local-label formats cannot be mixed: a label
must be defined and referred to using the same format.

   There's a minor caveat: just as for the ordinary local symbols, the
local symbols are translated into ordinary symbols using control
characters are to hide the ordinal number of the symbol.
Unfortunately, these symbols are not translated back in error messages.
Thus you may see confusing error messages when local symbols are used.
Control characters `\003' (control-C) and `\004' (control-D) are used
for the MMIX-specific local-symbol syntax.

   The symbol `Main' is handled specially; it is always global.

   By defining the symbols `__.MMIX.start..text' and
`__.MMIX.start..data', the address of respectively the `.text' and
`.data' segments of the final program can be defined, though when
linking more than one object file, the code or data in the object file
containing the symbol is not guaranteed to be start at that position;
just the final executable.  *Note MMIX-loc::.


File: as.info,  Node: MMIX-Regs,  Next: MMIX-Pseudos,  Prev: MMIX-Symbols,  Up: MMIX-Syntax

8.21.3.3 Register names
.......................

Local and global registers are specified as `$0' to `$255'.  The
recognized special register names are `rJ', `rA', `rB', `rC', `rD',
`rE', `rF', `rG', `rH', `rI', `rK', `rL', `rM', `rN', `rO', `rP', `rQ',
`rR', `rS', `rT', `rU', `rV', `rW', `rX', `rY', `rZ', `rBB', `rTT',
`rWW', `rXX', `rYY' and `rZZ'.  A leading `:' is optional for special
register names.

   Local and global symbols can be equated to register names and used in
place of ordinary registers.

   Similarly for special registers, local and global symbols can be
used.  Also, symbols equated from numbers and constant expressions are
allowed in place of a special register, except when either of the
options `--no-predefined-syms' and `--fixed-special-register-names' are
specified.  Then only the special register names above are allowed for
the instructions having a special register operand; `GET' and `PUT'.


File: as.info,  Node: MMIX-Pseudos,  Prev: MMIX-Regs,  Up: MMIX-Syntax

8.21.3.4 Assembler Directives
.............................

`LOC'
     The `LOC' directive sets the current location to the value of the
     operand field, which may include changing sections.  If the
     operand is a constant, the section is set to either `.data' if the
     value is `0x2000000000000000' or larger, else it is set to `.text'.
     Within a section, the current location may only be changed to
     monotonically higher addresses.  A LOC expression must be a
     previously defined symbol or a "pure" constant.

     An example, which sets the label PREV to the current location, and
     updates the current location to eight bytes forward:
          prev LOC @+8

     When a LOC has a constant as its operand, a symbol
     `__.MMIX.start..text' or `__.MMIX.start..data' is defined
     depending on the address as mentioned above.  Each such symbol is
     interpreted as special by the linker, locating the section at that
     address.  Note that if multiple files are linked, the first object
     file with that section will be mapped to that address (not
     necessarily the file with the LOC definition).

`LOCAL'
     Example:
           LOCAL external_symbol
           LOCAL 42
           .local asymbol

     This directive-operation generates a link-time assertion that the
     operand does not correspond to a global register.  The operand is
     an expression that at link-time resolves to a register symbol or a
     number.  A number is treated as the register having that number.
     There is one restriction on the use of this directive: the
     pseudo-directive must be placed in a section with contents, code
     or data.

`IS'
     The `IS' directive:
          asymbol IS an_expression
     sets the symbol `asymbol' to `an_expression'.  A symbol may not be
     set more than once using this directive.  Local labels may be set
     using this directive, for example:
          5H IS @+4

`GREG'
     This directive reserves a global register, gives it an initial
     value and optionally gives it a symbolic name.  Some examples:

          areg GREG
          breg GREG data_value
               GREG data_buffer
               .greg creg, another_data_value

     The symbolic register name can be used in place of a (non-special)
     register.  If a value isn't provided, it defaults to zero.  Unless
     the option `--no-merge-gregs' is specified, non-zero registers
     allocated with this directive may be eliminated by `as'; another
     register with the same value used in its place.  Any of the
     instructions `CSWAP', `GO', `LDA', `LDBU', `LDB', `LDHT', `LDOU',
     `LDO', `LDSF', `LDTU', `LDT', `LDUNC', `LDVTS', `LDWU', `LDW',
     `PREGO', `PRELD', `PREST', `PUSHGO', `STBU', `STB', `STCO', `STHT',
     `STOU', `STSF', `STTU', `STT', `STUNC', `SYNCD', `SYNCID', can
     have a value nearby an initial value in place of its second and
     third operands.  Here, "nearby" is defined as within the range
     0...255 from the initial value of such an allocated register.

          buffer1 BYTE 0,0,0,0,0
          buffer2 BYTE 0,0,0,0,0
           ...
           GREG buffer1
           LDOU $42,buffer2
     In the example above, the `Y' field of the `LDOUI' instruction
     (LDOU with a constant Z) will be replaced with the global register
     allocated for `buffer1', and the `Z' field will have the value 5,
     the offset from `buffer1' to `buffer2'.  The result is equivalent
     to this code:
          buffer1 BYTE 0,0,0,0,0
          buffer2 BYTE 0,0,0,0,0
           ...
          tmpreg GREG buffer1
           LDOU $42,tmpreg,(buffer2-buffer1)

     Global registers allocated with this directive are allocated in
     order higher-to-lower within a file.  Other than that, the exact
     order of register allocation and elimination is undefined.  For
     example, the order is undefined when more than one file with such
     directives are linked together.  With the options `-x' and
     `--linker-allocated-gregs', `GREG' directives for two-operand
     cases like the one mentioned above can be omitted.  Sufficient
     global registers will then be allocated by the linker.

`BYTE'
     The `BYTE' directive takes a series of operands separated by a
     comma.  If an operand is a string (*note Strings::), each
     character of that string is emitted as a byte.  Other operands
     must be constant expressions without forward references, in the
     range 0...255.  If you need operands having expressions with
     forward references, use `.byte' (*note Byte::).  An operand can be
     omitted, defaulting to a zero value.

`WYDE'
`TETRA'
`OCTA'
     The directives `WYDE', `TETRA' and `OCTA' emit constants of two,
     four and eight bytes size respectively.  Before anything else
     happens for the directive, the current location is aligned to the
     respective constant-size boundary.  If a label is defined at the
     beginning of the line, its value will be that after the alignment.
     A single operand can be omitted, defaulting to a zero value
     emitted for the directive.  Operands can be expressed as strings
     (*note Strings::), in which case each character in the string is
     emitted as a separate constant of the size indicated by the
     directive.

`PREFIX'
     The `PREFIX' directive sets a symbol name prefix to be prepended to
     all symbols (except local symbols, *note MMIX-Symbols::), that are
     not prefixed with `:', until the next `PREFIX' directive.  Such
     prefixes accumulate.  For example,
           PREFIX a
           PREFIX b
          c IS 0
     defines a symbol `abc' with the value 0.

`BSPEC'
`ESPEC'
     A pair of `BSPEC' and `ESPEC' directives delimit a section of
     special contents (without specified semantics).  Example:
           BSPEC 42
           TETRA 1,2,3
           ESPEC
     The single operand to `BSPEC' must be number in the range 0...255.
     The `BSPEC' number 80 is used by the GNU binutils implementation.


File: as.info,  Node: MMIX-mmixal,  Prev: MMIX-Syntax,  Up: MMIX-Dependent

8.21.4 Differences to `mmixal'
------------------------------

The binutils `as' and `ld' combination has a few differences in
function compared to `mmixal' (*note mmixsite::).

   The replacement of a symbol with a GREG-allocated register (*note
GREG-base::) is not handled the exactly same way in `as' as in
`mmixal'.  This is apparent in the `mmixal' example file `inout.mms',
where different registers with different offsets, eventually yielding
the same address, are used in the first instruction.  This type of
difference should however not affect the function of any program unless
it has specific assumptions about the allocated register number.

   Line numbers (in the `mmo' object format) are currently not
supported.

   Expression operator precedence is not that of mmixal: operator
precedence is that of the C programming language.  It's recommended to
use parentheses to explicitly specify wanted operator precedence
whenever more than one type of operators are used.

   The serialize unary operator `&', the fractional division operator
`//', the logical not operator `!' and the modulus operator `%' are not
available.

   Symbols are not global by default, unless the option
`--globalize-symbols' is passed.  Use the `.global' directive to
globalize symbols (*note Global::).

   Operand syntax is a bit stricter with `as' than `mmixal'.  For
example, you can't say `addu 1,2,3', instead you must write `addu
$1,$2,3'.

   You can't LOC to a lower address than those already visited (i.e.
"backwards").

   A LOC directive must come before any emitted code.

   Predefined symbols are visible as file-local symbols after use.  (In
the ELF file, that is--the linked mmo file has no notion of a file-local
symbol.)

   Some mapping of constant expressions to sections in LOC expressions
is attempted, but that functionality is easily confused and should be
avoided unless compatibility with `mmixal' is required.  A LOC
expression to `0x2000000000000000' or higher, maps to the `.data'
section and lower addresses map to the `.text' section (*note
MMIX-loc::).

   The code and data areas are each contiguous.  Sparse programs with
far-away LOC directives will take up the same amount of space as a
contiguous program with zeros filled in the gaps between the LOC
directives.  If you need sparse programs, you might try and get the
wanted effect with a linker script and splitting up the code parts into
sections (*note Section::).  Assembly code for this, to be compatible
with `mmixal', would look something like:
      .if 0
      LOC away_expression
      .else
      .section away,"ax"
      .fi
   `as' will not execute the LOC directive and `mmixal' ignores the
lines with `.'.  This construct can be used generally to help
compatibility.

   Symbols can't be defined twice-not even to the same value.

   Instruction mnemonics are recognized case-insensitive, though the
`IS' and `GREG' pseudo-operations must be specified in upper-case
characters.

   There's no unicode support.

   The following is a list of programs in `mmix.tar.gz', available at
`http://www-cs-faculty.stanford.edu/~knuth/mmix-news.html', last
checked with the version dated 2001-08-25 (md5sum
c393470cfc86fac040487d22d2bf0172) that assemble with `mmixal' but do
not assemble with `as':

`silly.mms'
     LOC to a previous address.

`sim.mms'
     Redefines symbol `Done'.

`test.mms'
     Uses the serial operator `&'.


File: as.info,  Node: MSP430-Dependent,  Next: SH-Dependent,  Prev: MMIX-Dependent,  Up: Machine Dependencies

8.22 MSP 430 Dependent Features
===============================

* Menu:

* MSP430 Options::              Options
* MSP430 Syntax::               Syntax
* MSP430 Floating Point::       Floating Point
* MSP430 Directives::           MSP 430 Machine Directives
* MSP430 Opcodes::              Opcodes
* MSP430 Profiling Capability::	Profiling Capability


File: as.info,  Node: MSP430 Options,  Next: MSP430 Syntax,  Up: MSP430-Dependent

8.22.1 Options
--------------

`-m'
     select the mpu arch. Currently has no effect.

`-mP'
     enables polymorph instructions handler.

`-mQ'
     enables relaxation at assembly time. DANGEROUS!



File: as.info,  Node: MSP430 Syntax,  Next: MSP430 Floating Point,  Prev: MSP430 Options,  Up: MSP430-Dependent

8.22.2 Syntax
-------------

* Menu:

* MSP430-Macros::		Macros
* MSP430-Chars::                Special Characters
* MSP430-Regs::                 Register Names
* MSP430-Ext::			Assembler Extensions


File: as.info,  Node: MSP430-Macros,  Next: MSP430-Chars,  Up: MSP430 Syntax

8.22.2.1 Macros
...............

The macro syntax used on the MSP 430 is like that described in the MSP
430 Family Assembler Specification.  Normal `as' macros should still
work.

   Additional built-in macros are:

`llo(exp)'
     Extracts least significant word from 32-bit expression 'exp'.

`lhi(exp)'
     Extracts most significant word from 32-bit expression 'exp'.

`hlo(exp)'
     Extracts 3rd word from 64-bit expression 'exp'.

`hhi(exp)'
     Extracts 4rd word from 64-bit expression 'exp'.


   They normally being used as an immediate source operand.
         mov	#llo(1), r10	;	== mov	#1, r10
         mov	#lhi(1), r10	;	== mov	#0, r10


File: as.info,  Node: MSP430-Chars,  Next: MSP430-Regs,  Prev: MSP430-Macros,  Up: MSP430 Syntax

8.22.2.2 Special Characters
...........................

`;' is the line comment character.

   The character `$' in jump instructions indicates current location and
implemented only for TI syntax compatibility.


File: as.info,  Node: MSP430-Regs,  Next: MSP430-Ext,  Prev: MSP430-Chars,  Up: MSP430 Syntax

8.22.2.3 Register Names
.......................

General-purpose registers are represented by predefined symbols of the
form `rN' (for global registers), where N represents a number between
`0' and `15'.  The leading letters may be in either upper or lower
case; for example, `r13' and `R7' are both valid register names.

   Register names `PC', `SP' and `SR' cannot be used as register names
and will be treated as variables. Use `r0', `r1', and `r2' instead.


File: as.info,  Node: MSP430-Ext,  Prev: MSP430-Regs,  Up: MSP430 Syntax

8.22.2.4 Assembler Extensions
.............................

`@rN'
     As destination operand being treated as `0(rn)'

`0(rN)'
     As source operand being treated as `@rn'

`jCOND +N'
     Skips next N bytes followed by jump instruction and equivalent to
     `jCOND $+N+2'


   Also, there are some instructions, which cannot be found in other
assemblers.  These are branch instructions, which has different opcodes
upon jump distance.  They all got PC relative addressing mode.

`beq label'
     A polymorph instruction which is `jeq label' in case if jump
     distance within allowed range for cpu's jump instruction. If not,
     this unrolls into a sequence of
            jne $+6
            br  label

`bne label'
     A polymorph instruction which is `jne label' or `jeq +4; br label'

`blt label'
     A polymorph instruction which is `jl label' or `jge +4; br label'

`bltn label'
     A polymorph instruction which is `jn label' or `jn +2; jmp +4; br
     label'

`bltu label'
     A polymorph instruction which is `jlo label' or `jhs +2; br label'

`bge label'
     A polymorph instruction which is `jge label' or `jl +4; br label'

`bgeu label'
     A polymorph instruction which is `jhs label' or `jlo +4; br label'

`bgt label'
     A polymorph instruction which is `jeq +2; jge label' or `jeq +6;
     jl  +4; br label'

`bgtu label'
     A polymorph instruction which is `jeq +2; jhs label' or `jeq +6;
     jlo +4; br label'

`bleu label'
     A polymorph instruction which is `jeq label; jlo label' or `jeq
     +2; jhs +4; br label'

`ble label'
     A polymorph instruction which is `jeq label; jl  label' or `jeq
     +2; jge +4; br label'

`jump label'
     A polymorph instruction which is `jmp label' or `br label'


File: as.info,  Node: MSP430 Floating Point,  Next: MSP430 Directives,  Prev: MSP430 Syntax,  Up: MSP430-Dependent

8.22.3 Floating Point
---------------------

The MSP 430 family uses IEEE 32-bit floating-point numbers.


File: as.info,  Node: MSP430 Directives,  Next: MSP430 Opcodes,  Prev: MSP430 Floating Point,  Up: MSP430-Dependent

8.22.4 MSP 430 Machine Directives
---------------------------------

`.file'
     This directive is ignored; it is accepted for compatibility with
     other MSP 430 assemblers.

          _Warning:_ in other versions of the GNU assembler, `.file' is
          used for the directive called `.app-file' in the MSP 430
          support.

`.line'
     This directive is ignored; it is accepted for compatibility with
     other MSP 430 assemblers.

`.arch'
     Currently this directive is ignored; it is accepted for
     compatibility with other MSP 430 assemblers.

`.profiler'
     This directive instructs assembler to add new profile entry to the
     object file.



File: as.info,  Node: MSP430 Opcodes,  Next: MSP430 Profiling Capability,  Prev: MSP430 Directives,  Up: MSP430-Dependent

8.22.5 Opcodes
--------------

`as' implements all the standard MSP 430 opcodes.  No additional
pseudo-instructions are needed on this family.

   For information on the 430 machine instruction set, see `MSP430
User's Manual, document slau049d', Texas Instrument, Inc.


File: as.info,  Node: MSP430 Profiling Capability,  Prev: MSP430 Opcodes,  Up: MSP430-Dependent

8.22.6 Profiling Capability
---------------------------

It is a performance hit to use gcc's profiling approach for this tiny
target.  Even more - jtag hardware facility does not perform any
profiling functions.  However we've got gdb's built-in simulator where
we can do anything.

   We define new section `.profiler' which holds all profiling
information.  We define new pseudo operation `.profiler' which will
instruct assembler to add new profile entry to the object file. Profile
should take place at the present address.

   Pseudo operation format:

   `.profiler flags,function_to_profile [, cycle_corrector, extra]'

   where:

          `flags' is a combination of the following characters:

    `s'
          function entry

    `x'
          function exit

    `i'
          function is in init section

    `f'
          function is in fini section

    `l'
          library call

    `c'
          libc standard call

    `d'
          stack value demand

    `I'
          interrupt service routine

    `P'
          prologue start

    `p'
          prologue end

    `E'
          epilogue start

    `e'
          epilogue end

    `j'
          long jump / sjlj unwind

    `a'
          an arbitrary code fragment

    `t'
          extra parameter saved (a constant value like frame size)

`function_to_profile'
     a function address

`cycle_corrector'
     a value which should be added to the cycle counter, zero if
     omitted.

`extra'
     any extra parameter, zero if omitted.


   For example:
     .global fxx
     .type fxx,@function
     fxx:
     .LFrameOffset_fxx=0x08
     .profiler "scdP", fxx     ; function entry.
     			  ; we also demand stack value to be saved
       push r11
       push r10
       push r9
       push r8
     .profiler "cdpt",fxx,0, .LFrameOffset_fxx  ; check stack value at this point
     					  ; (this is a prologue end)
     					  ; note, that spare var filled with
     					  ; the farme size
       mov r15,r8
     ...
     .profiler cdE,fxx         ; check stack
       pop r8
       pop r9
       pop r10
       pop r11
     .profiler xcde,fxx,3      ; exit adds 3 to the cycle counter
       ret                     ; cause 'ret' insn takes 3 cycles


File: as.info,  Node: PDP-11-Dependent,  Next: PJ-Dependent,  Prev: SH64-Dependent,  Up: Machine Dependencies

8.23 PDP-11 Dependent Features
==============================

* Menu:

* PDP-11-Options::		Options
* PDP-11-Pseudos::		Assembler Directives
* PDP-11-Syntax::		DEC Syntax versus BSD Syntax
* PDP-11-Mnemonics::		Instruction Naming
* PDP-11-Synthetic::		Synthetic Instructions


File: as.info,  Node: PDP-11-Options,  Next: PDP-11-Pseudos,  Up: PDP-11-Dependent

8.23.1 Options
--------------

The PDP-11 version of `as' has a rich set of machine dependent options.

8.23.1.1 Code Generation Options
................................

`-mpic | -mno-pic'
     Generate position-independent (or position-dependent) code.

     The default is to generate position-independent code.

8.23.1.2 Instruction Set Extension Options
..........................................

These options enables or disables the use of extensions over the base
line instruction set as introduced by the first PDP-11 CPU: the KA11.
Most options come in two variants: a `-m'EXTENSION that enables
EXTENSION, and a `-mno-'EXTENSION that disables EXTENSION.

   The default is to enable all extensions.

`-mall | -mall-extensions'
     Enable all instruction set extensions.

`-mno-extensions'
     Disable all instruction set extensions.

`-mcis | -mno-cis'
     Enable (or disable) the use of the commercial instruction set,
     which consists of these instructions: `ADDNI', `ADDN', `ADDPI',
     `ADDP', `ASHNI', `ASHN', `ASHPI', `ASHP', `CMPCI', `CMPC',
     `CMPNI', `CMPN', `CMPPI', `CMPP', `CVTLNI', `CVTLN', `CVTLPI',
     `CVTLP', `CVTNLI', `CVTNL', `CVTNPI', `CVTNP', `CVTPLI', `CVTPL',
     `CVTPNI', `CVTPN', `DIVPI', `DIVP', `L2DR', `L3DR', `LOCCI',
     `LOCC', `MATCI', `MATC', `MOVCI', `MOVC', `MOVRCI', `MOVRC',
     `MOVTCI', `MOVTC', `MULPI', `MULP', `SCANCI', `SCANC', `SKPCI',
     `SKPC', `SPANCI', `SPANC', `SUBNI', `SUBN', `SUBPI', and `SUBP'.

`-mcsm | -mno-csm'
     Enable (or disable) the use of the `CSM' instruction.

`-meis | -mno-eis'
     Enable (or disable) the use of the extended instruction set, which
     consists of these instructions: `ASHC', `ASH', `DIV', `MARK',
     `MUL', `RTT', `SOB' `SXT', and `XOR'.

`-mfis | -mkev11'
`-mno-fis | -mno-kev11'
     Enable (or disable) the use of the KEV11 floating-point
     instructions: `FADD', `FDIV', `FMUL', and `FSUB'.

`-mfpp | -mfpu | -mfp-11'
`-mno-fpp | -mno-fpu | -mno-fp-11'
     Enable (or disable) the use of FP-11 floating-point instructions:
     `ABSF', `ADDF', `CFCC', `CLRF', `CMPF', `DIVF', `LDCFF', `LDCIF',
     `LDEXP', `LDF', `LDFPS', `MODF', `MULF', `NEGF', `SETD', `SETF',
     `SETI', `SETL', `STCFF', `STCFI', `STEXP', `STF', `STFPS', `STST',
     `SUBF', and `TSTF'.

`-mlimited-eis | -mno-limited-eis'
     Enable (or disable) the use of the limited extended instruction
     set: `MARK', `RTT', `SOB', `SXT', and `XOR'.

     The -mno-limited-eis options also implies -mno-eis.

`-mmfpt | -mno-mfpt'
     Enable (or disable) the use of the `MFPT' instruction.

`-mmultiproc | -mno-multiproc'
     Enable (or disable) the use of multiprocessor instructions:
     `TSTSET' and `WRTLCK'.

`-mmxps | -mno-mxps'
     Enable (or disable) the use of the `MFPS' and `MTPS' instructions.

`-mspl | -mno-spl'
     Enable (or disable) the use of the `SPL' instruction.

     Enable (or disable) the use of the microcode instructions: `LDUB',
     `MED', and `XFC'.

8.23.1.3 CPU Model Options
..........................

These options enable the instruction set extensions supported by a
particular CPU, and disables all other extensions.

`-mka11'
     KA11 CPU.  Base line instruction set only.

`-mkb11'
     KB11 CPU.  Enable extended instruction set and `SPL'.

`-mkd11a'
     KD11-A CPU.  Enable limited extended instruction set.

`-mkd11b'
     KD11-B CPU.  Base line instruction set only.

`-mkd11d'
     KD11-D CPU.  Base line instruction set only.

`-mkd11e'
     KD11-E CPU.  Enable extended instruction set, `MFPS', and `MTPS'.

`-mkd11f | -mkd11h | -mkd11q'
     KD11-F, KD11-H, or KD11-Q CPU.  Enable limited extended
     instruction set, `MFPS', and `MTPS'.

`-mkd11k'
     KD11-K CPU.  Enable extended instruction set, `LDUB', `MED',
     `MFPS', `MFPT', `MTPS', and `XFC'.

`-mkd11z'
     KD11-Z CPU.  Enable extended instruction set, `CSM', `MFPS',
     `MFPT', `MTPS', and `SPL'.

`-mf11'
     F11 CPU.  Enable extended instruction set, `MFPS', `MFPT', and
     `MTPS'.

`-mj11'
     J11 CPU.  Enable extended instruction set, `CSM', `MFPS', `MFPT',
     `MTPS', `SPL', `TSTSET', and `WRTLCK'.

`-mt11'
     T11 CPU.  Enable limited extended instruction set, `MFPS', and
     `MTPS'.

8.23.1.4 Machine Model Options
..............................

These options enable the instruction set extensions supported by a
particular machine model, and disables all other extensions.

`-m11/03'
     Same as `-mkd11f'.

`-m11/04'
     Same as `-mkd11d'.

`-m11/05 | -m11/10'
     Same as `-mkd11b'.

`-m11/15 | -m11/20'
     Same as `-mka11'.

`-m11/21'
     Same as `-mt11'.

`-m11/23 | -m11/24'
     Same as `-mf11'.

`-m11/34'
     Same as `-mkd11e'.

`-m11/34a'
     Ame as `-mkd11e' `-mfpp'.

`-m11/35 | -m11/40'
     Same as `-mkd11a'.

`-m11/44'
     Same as `-mkd11z'.

`-m11/45 | -m11/50 | -m11/55 | -m11/70'
     Same as `-mkb11'.

`-m11/53 | -m11/73 | -m11/83 | -m11/84 | -m11/93 | -m11/94'
     Same as `-mj11'.

`-m11/60'
     Same as `-mkd11k'.


File: as.info,  Node: PDP-11-Pseudos,  Next: PDP-11-Syntax,  Prev: PDP-11-Options,  Up: PDP-11-Dependent

8.23.2 Assembler Directives
---------------------------

The PDP-11 version of `as' has a few machine dependent assembler
directives.

`.bss'
     Switch to the `bss' section.

`.even'
     Align the location counter to an even number.


File: as.info,  Node: PDP-11-Syntax,  Next: PDP-11-Mnemonics,  Prev: PDP-11-Pseudos,  Up: PDP-11-Dependent

8.23.3 PDP-11 Assembly Language Syntax
--------------------------------------

`as' supports both DEC syntax and BSD syntax.  The only difference is
that in DEC syntax, a `#' character is used to denote an immediate
constants, while in BSD syntax the character for this purpose is `$'.

   eneral-purpose registers are named `r0' through `r7'.  Mnemonic
alternatives for `r6' and `r7' are `sp' and `pc', respectively.

   Floating-point registers are named `ac0' through `ac3', or
alternatively `fr0' through `fr3'.

   Comments are started with a `#' or a `/' character, and extend to
the end of the line.  (FIXME: clash with immediates?)


File: as.info,  Node: PDP-11-Mnemonics,  Next: PDP-11-Synthetic,  Prev: PDP-11-Syntax,  Up: PDP-11-Dependent

8.23.4 Instruction Naming
-------------------------

Some instructions have alternative names.

`BCC'
     `BHIS'

`BCS'
     `BLO'

`L2DR'
     `L2D'

`L3DR'
     `L3D'

`SYS'
     `TRAP'


File: as.info,  Node: PDP-11-Synthetic,  Prev: PDP-11-Mnemonics,  Up: PDP-11-Dependent

8.23.5 Synthetic Instructions
-----------------------------

The `JBR' and `J'CC synthetic instructions are not supported yet.


File: as.info,  Node: PJ-Dependent,  Next: PPC-Dependent,  Prev: PDP-11-Dependent,  Up: Machine Dependencies

8.24 picoJava Dependent Features
================================

* Menu:

* PJ Options::              Options


File: as.info,  Node: PJ Options,  Up: PJ-Dependent

8.24.1 Options
--------------

`as' has two additional command-line options for the picoJava
architecture.
`-ml'
     This option selects little endian data output.

`-mb'
     This option selects big endian data output.


File: as.info,  Node: PPC-Dependent,  Next: Sparc-Dependent,  Prev: PJ-Dependent,  Up: Machine Dependencies

8.25 PowerPC Dependent Features
===============================

* Menu:

* PowerPC-Opts::                Options
* PowerPC-Pseudo::              PowerPC Assembler Directives


File: as.info,  Node: PowerPC-Opts,  Next: PowerPC-Pseudo,  Up: PPC-Dependent

8.25.1 Options
--------------

The PowerPC chip family includes several successive levels, using the
same core instruction set, but including a few additional instructions
at each level.  There are exceptions to this however.  For details on
what instructions each variant supports, please see the chip's
architecture reference manual.

   The following table lists all available PowerPC options.

`-mpwrx | -mpwr2'
     Generate code for POWER/2 (RIOS2).

`-mpwr'
     Generate code for POWER (RIOS1)

`-m601'
     Generate code for PowerPC 601.

`-mppc, -mppc32, -m603, -m604'
     Generate code for PowerPC 603/604.

`-m403, -m405'
     Generate code for PowerPC 403/405.

`-m440'
     Generate code for PowerPC 440.  BookE and some 405 instructions.

`-m7400, -m7410, -m7450, -m7455'
     Generate code for PowerPC 7400/7410/7450/7455.

`-mppc64, -m620'
     Generate code for PowerPC 620/625/630.

`-mppc64bridge'
     Generate code for PowerPC 64, including bridge insns.

`-mbooke64'
     Generate code for 64-bit BookE.

`-mbooke, mbooke32'
     Generate code for 32-bit BookE.

`-me300'
     Generate code for PowerPC e300 family.

`-maltivec'
     Generate code for processors with AltiVec instructions.

`-mpower4'
     Generate code for Power4 architecture.

`-mpower5'
     Generate code for Power5 architecture.

`-mcom'
     Generate code Power/PowerPC common instructions.

`-many'
     Generate code for any architecture (PWR/PWRX/PPC).

`-mregnames'
     Allow symbolic names for registers.

`-mno-regnames'
     Do not allow symbolic names for registers.

`-mrelocatable'
     Support for GCC's -mrelocatble option.

`-mrelocatable-lib'
     Support for GCC's -mrelocatble-lib option.

`-memb'
     Set PPC_EMB bit in ELF flags.

`-mlittle, -mlittle-endian'
     Generate code for a little endian machine.

`-mbig, -mbig-endian'
     Generate code for a big endian machine.

`-msolaris'
     Generate code for Solaris.

`-mno-solaris'
     Do not generate code for Solaris.


File: as.info,  Node: PowerPC-Pseudo,  Prev: PowerPC-Opts,  Up: PPC-Dependent

8.25.2 PowerPC Assembler Directives
-----------------------------------

A number of assembler directives are available for PowerPC.  The
following table is far from complete.

`.machine "string"'
     This directive allows you to change the machine for which code is
     generated.  `"string"' may be any of the -m cpu selection options
     (without the -m) enclosed in double quotes, `"push"', or `"pop"'.
     `.machine "push"' saves the currently selected cpu, which may be
     restored with `.machine "pop"'.


File: as.info,  Node: SH-Dependent,  Next: SH64-Dependent,  Prev: MSP430-Dependent,  Up: Machine Dependencies

8.26 Renesas / SuperH SH Dependent Features
===========================================

* Menu:

* SH Options::              Options
* SH Syntax::               Syntax
* SH Floating Point::       Floating Point
* SH Directives::           SH Machine Directives
* SH Opcodes::              Opcodes


File: as.info,  Node: SH Options,  Next: SH Syntax,  Up: SH-Dependent

8.26.1 Options
--------------

`as' has following command-line options for the Renesas (formerly
Hitachi) / SuperH SH family.

`--little'
     Generate little endian code.

`--big'
     Generate big endian code.

`--relax'
     Alter jump instructions for long displacements.

`--small'
     Align sections to 4 byte boundaries, not 16.

`--dsp'
     Enable sh-dsp insns, and disable sh3e / sh4 insns.

`--renesas'
     Disable optimization with section symbol for compatibility with
     Renesas assembler.

`--allow-reg-prefix'
     Allow '$' as a register name prefix.

`--isa=sh4 | sh4a'
     Specify the sh4 or sh4a instruction set.

`--isa=dsp'
     Enable sh-dsp insns, and disable sh3e / sh4 insns.

`--isa=fp'
     Enable sh2e, sh3e, sh4, and sh4a insn sets.

`--isa=all'
     Enable sh1, sh2, sh2e, sh3, sh3e, sh4, sh4a, and sh-dsp insn sets.



File: as.info,  Node: SH Syntax,  Next: SH Floating Point,  Prev: SH Options,  Up: SH-Dependent

8.26.2 Syntax
-------------

* Menu:

* SH-Chars::                Special Characters
* SH-Regs::                 Register Names
* SH-Addressing::           Addressing Modes


File: as.info,  Node: SH-Chars,  Next: SH-Regs,  Up: SH Syntax

8.26.2.1 Special Characters
...........................

`!' is the line comment character.

   You can use `;' instead of a newline to separate statements.

   Since `$' has no special meaning, you may use it in symbol names.


File: as.info,  Node: SH-Regs,  Next: SH-Addressing,  Prev: SH-Chars,  Up: SH Syntax

8.26.2.2 Register Names
.......................

You can use the predefined symbols `r0', `r1', `r2', `r3', `r4', `r5',
`r6', `r7', `r8', `r9', `r10', `r11', `r12', `r13', `r14', and `r15' to
refer to the SH registers.

   The SH also has these control registers:

`pr'
     procedure register (holds return address)

`pc'
     program counter

`mach'
`macl'
     high and low multiply accumulator registers

`sr'
     status register

`gbr'
     global base register

`vbr'
     vector base register (for interrupt vectors)


File: as.info,  Node: SH-Addressing,  Prev: SH-Regs,  Up: SH Syntax

8.26.2.3 Addressing Modes
.........................

`as' understands the following addressing modes for the SH.  `RN' in
the following refers to any of the numbered registers, but _not_ the
control registers.

`RN'
     Register direct

`@RN'
     Register indirect

`@-RN'
     Register indirect with pre-decrement

`@RN+'
     Register indirect with post-increment

`@(DISP, RN)'
     Register indirect with displacement

`@(R0, RN)'
     Register indexed

`@(DISP, GBR)'
     `GBR' offset

`@(R0, GBR)'
     GBR indexed

`ADDR'
`@(DISP, PC)'
     PC relative address (for branch or for addressing memory).  The
     `as' implementation allows you to use the simpler form ADDR
     anywhere a PC relative address is called for; the alternate form
     is supported for compatibility with other assemblers.

`#IMM'
     Immediate data


File: as.info,  Node: SH Floating Point,  Next: SH Directives,  Prev: SH Syntax,  Up: SH-Dependent

8.26.3 Floating Point
---------------------

SH2E, SH3E and SH4 groups have on-chip floating-point unit (FPU). Other
SH groups can use `.float' directive to generate IEEE floating-point
numbers.

   SH2E and SH3E support single-precision floating point calculations as
well as entirely PCAPI compatible emulation of double-precision
floating point calculations. SH2E and SH3E instructions are a subset of
the floating point calculations conforming to the IEEE754 standard.

   In addition to single-precision and double-precision floating-point
operation capability, the on-chip FPU of SH4 has a 128-bit graphic
engine that enables 32-bit floating-point data to be processed 128 bits
at a time. It also supports 4 * 4 array operations and inner product
operations. Also, a superscalar architecture is employed that enables
simultaneous execution of two instructions (including FPU
instructions), providing performance of up to twice that of
conventional architectures at the same frequency.


File: as.info,  Node: SH Directives,  Next: SH Opcodes,  Prev: SH Floating Point,  Up: SH-Dependent

8.26.4 SH Machine Directives
----------------------------

`uaword'
`ualong'
     `as' will issue a warning when a misaligned `.word' or `.long'
     directive is used.  You may use `.uaword' or `.ualong' to indicate
     that the value is intentionally misaligned.


File: as.info,  Node: SH Opcodes,  Prev: SH Directives,  Up: SH-Dependent

8.26.5 Opcodes
--------------

For detailed information on the SH machine instruction set, see
`SH-Microcomputer User's Manual' (Renesas) or `SH-4 32-bit CPU Core
Architecture' (SuperH) and `SuperH (SH) 64-Bit RISC Series' (SuperH).

   `as' implements all the standard SH opcodes.  No additional
pseudo-instructions are needed on this family.  Note, however, that
because `as' supports a simpler form of PC-relative addressing, you may
simply write (for example)

     mov.l  bar,r0

where other assemblers might require an explicit displacement to `bar'
from the program counter:

     mov.l  @(DISP, PC)

   Here is a summary of SH opcodes:

     Legend:
     Rn        a numbered register
     Rm        another numbered register
     #imm      immediate data
     disp      displacement
     disp8     8-bit displacement
     disp12    12-bit displacement

     add #imm,Rn                    lds.l @Rn+,PR
     add Rm,Rn                      mac.w @Rm+,@Rn+
     addc Rm,Rn                     mov #imm,Rn
     addv Rm,Rn                     mov Rm,Rn
     and #imm,R0                    mov.b Rm,@(R0,Rn)
     and Rm,Rn                      mov.b Rm,@-Rn
     and.b #imm,@(R0,GBR)           mov.b Rm,@Rn
     bf disp8                       mov.b @(disp,Rm),R0
     bra disp12                     mov.b @(disp,GBR),R0
     bsr disp12                     mov.b @(R0,Rm),Rn
     bt disp8                       mov.b @Rm+,Rn
     clrmac                         mov.b @Rm,Rn
     clrt                           mov.b R0,@(disp,Rm)
     cmp/eq #imm,R0                 mov.b R0,@(disp,GBR)
     cmp/eq Rm,Rn                   mov.l Rm,@(disp,Rn)
     cmp/ge Rm,Rn                   mov.l Rm,@(R0,Rn)
     cmp/gt Rm,Rn                   mov.l Rm,@-Rn
     cmp/hi Rm,Rn                   mov.l Rm,@Rn
     cmp/hs Rm,Rn                   mov.l @(disp,Rn),Rm
     cmp/pl Rn                      mov.l @(disp,GBR),R0
     cmp/pz Rn                      mov.l @(disp,PC),Rn
     cmp/str Rm,Rn                  mov.l @(R0,Rm),Rn
     div0s Rm,Rn                    mov.l @Rm+,Rn
     div0u                          mov.l @Rm,Rn
     div1 Rm,Rn                     mov.l R0,@(disp,GBR)
     exts.b Rm,Rn                   mov.w Rm,@(R0,Rn)
     exts.w Rm,Rn                   mov.w Rm,@-Rn
     extu.b Rm,Rn                   mov.w Rm,@Rn
     extu.w Rm,Rn                   mov.w @(disp,Rm),R0
     jmp @Rn                        mov.w @(disp,GBR),R0
     jsr @Rn                        mov.w @(disp,PC),Rn
     ldc Rn,GBR                     mov.w @(R0,Rm),Rn
     ldc Rn,SR                      mov.w @Rm+,Rn
     ldc Rn,VBR                     mov.w @Rm,Rn
     ldc.l @Rn+,GBR                 mov.w R0,@(disp,Rm)
     ldc.l @Rn+,SR                  mov.w R0,@(disp,GBR)
     ldc.l @Rn+,VBR                 mova @(disp,PC),R0
     lds Rn,MACH                    movt Rn
     lds Rn,MACL                    muls Rm,Rn
     lds Rn,PR                      mulu Rm,Rn
     lds.l @Rn+,MACH                neg Rm,Rn
     lds.l @Rn+,MACL                negc Rm,Rn

     nop                            stc VBR,Rn
     not Rm,Rn                      stc.l GBR,@-Rn
     or #imm,R0                     stc.l SR,@-Rn
     or Rm,Rn                       stc.l VBR,@-Rn
     or.b #imm,@(R0,GBR)            sts MACH,Rn
     rotcl Rn                       sts MACL,Rn
     rotcr Rn                       sts PR,Rn
     rotl Rn                        sts.l MACH,@-Rn
     rotr Rn                        sts.l MACL,@-Rn
     rte                            sts.l PR,@-Rn
     rts                            sub Rm,Rn
     sett                           subc Rm,Rn
     shal Rn                        subv Rm,Rn
     shar Rn                        swap.b Rm,Rn
     shll Rn                        swap.w Rm,Rn
     shll16 Rn                      tas.b @Rn
     shll2 Rn                       trapa #imm
     shll8 Rn                       tst #imm,R0
     shlr Rn                        tst Rm,Rn
     shlr16 Rn                      tst.b #imm,@(R0,GBR)
     shlr2 Rn                       xor #imm,R0
     shlr8 Rn                       xor Rm,Rn
     sleep                          xor.b #imm,@(R0,GBR)
     stc GBR,Rn                     xtrct Rm,Rn
     stc SR,Rn


File: as.info,  Node: SH64-Dependent,  Next: PDP-11-Dependent,  Prev: SH-Dependent,  Up: Machine Dependencies

8.27 SuperH SH64 Dependent Features
===================================

* Menu:

* SH64 Options::              Options
* SH64 Syntax::               Syntax
* SH64 Directives::           SH64 Machine Directives
* SH64 Opcodes::              Opcodes


File: as.info,  Node: SH64 Options,  Next: SH64 Syntax,  Up: SH64-Dependent

8.27.1 Options
--------------

`-isa=sh4 | sh4a'
     Specify the sh4 or sh4a instruction set.

`-isa=dsp'
     Enable sh-dsp insns, and disable sh3e / sh4 insns.

`-isa=fp'
     Enable sh2e, sh3e, sh4, and sh4a insn sets.

`-isa=all'
     Enable sh1, sh2, sh2e, sh3, sh3e, sh4, sh4a, and sh-dsp insn sets.

`-isa=shmedia | -isa=shcompact'
     Specify the default instruction set.  `SHmedia' specifies the
     32-bit opcodes, and `SHcompact' specifies the 16-bit opcodes
     compatible with previous SH families.  The default depends on the
     ABI selected; the default for the 64-bit ABI is SHmedia, and the
     default for the 32-bit ABI is SHcompact.  If neither the ABI nor
     the ISA is specified, the default is 32-bit SHcompact.

     Note that the `.mode' pseudo-op is not permitted if the ISA is not
     specified on the command line.

`-abi=32 | -abi=64'
     Specify the default ABI.  If the ISA is specified and the ABI is
     not, the default ABI depends on the ISA, with SHmedia defaulting
     to 64-bit and SHcompact defaulting to 32-bit.

     Note that the `.abi' pseudo-op is not permitted if the ABI is not
     specified on the command line.  When the ABI is specified on the
     command line, any `.abi' pseudo-ops in the source must match it.

`-shcompact-const-crange'
     Emit code-range descriptors for constants in SHcompact code
     sections.

`-no-mix'
     Disallow SHmedia code in the same section as constants and
     SHcompact code.

`-no-expand'
     Do not expand MOVI, PT, PTA or PTB instructions.

`-expand-pt32'
     With -abi=64, expand PT, PTA and PTB instructions to 32 bits only.



File: as.info,  Node: SH64 Syntax,  Next: SH64 Directives,  Prev: SH64 Options,  Up: SH64-Dependent

8.27.2 Syntax
-------------

* Menu:

* SH64-Chars::                Special Characters
* SH64-Regs::                 Register Names
* SH64-Addressing::           Addressing Modes


File: as.info,  Node: SH64-Chars,  Next: SH64-Regs,  Up: SH64 Syntax

8.27.2.1 Special Characters
...........................

`!' is the line comment character.

   You can use `;' instead of a newline to separate statements.

   Since `$' has no special meaning, you may use it in symbol names.


File: as.info,  Node: SH64-Regs,  Next: SH64-Addressing,  Prev: SH64-Chars,  Up: SH64 Syntax

8.27.2.2 Register Names
.......................

You can use the predefined symbols `r0' through `r63' to refer to the
SH64 general registers, `cr0' through `cr63' for control registers,
`tr0' through `tr7' for target address registers, `fr0' through `fr63'
for single-precision floating point registers, `dr0' through `dr62'
(even numbered registers only) for double-precision floating point
registers, `fv0' through `fv60' (multiples of four only) for
single-precision floating point vectors, `fp0' through `fp62' (even
numbered registers only) for single-precision floating point pairs,
`mtrx0' through `mtrx48' (multiples of 16 only) for 4x4 matrices of
single-precision floating point registers, `pc' for the program
counter, and `fpscr' for the floating point status and control register.

   You can also refer to the control registers by the mnemonics `sr',
`ssr', `pssr', `intevt', `expevt', `pexpevt', `tra', `spc', `pspc',
`resvec', `vbr', `tea', `dcr', `kcr0', `kcr1', `ctc', and `usr'.


File: as.info,  Node: SH64-Addressing,  Prev: SH64-Regs,  Up: SH64 Syntax

8.27.2.3 Addressing Modes
.........................

SH64 operands consist of either a register or immediate value.  The
immediate value can be a constant or label reference (or portion of a
label reference), as in this example:

     	movi	4,r2
     	pt	function, tr4
     	movi	(function >> 16) & 65535,r0
     	shori	function & 65535, r0
     	ld.l	r0,4,r0

   Instruction label references can reference labels in either SHmedia
or SHcompact.  To differentiate between the two, labels in SHmedia
sections will always have the least significant bit set (i.e. they will
be odd), which SHcompact labels will have the least significant bit
reset (i.e. they will be even).  If you need to reference the actual
address of a label, you can use the `datalabel' modifier, as in this
example:

     	.long	function
     	.long	datalabel function

   In that example, the first longword may or may not have the least
significant bit set depending on whether the label is an SHmedia label
or an SHcompact label.  The second longword will be the actual address
of the label, regardless of what type of label it is.


File: as.info,  Node: SH64 Directives,  Next: SH64 Opcodes,  Prev: SH64 Syntax,  Up: SH64-Dependent

8.27.3 SH64 Machine Directives
------------------------------

In addition to the SH directives, the SH64 provides the following
directives:

`.mode [shmedia|shcompact]'
`.isa [shmedia|shcompact]'
     Specify the ISA for the following instructions (the two directives
     are equivalent).  Note that programs such as `objdump' rely on
     symbolic labels to determine when such mode switches occur (by
     checking the least significant bit of the label's address), so
     such mode/isa changes should always be followed by a label (in
     practice, this is true anyway).  Note that you cannot use these
     directives if you didn't specify an ISA on the command line.

`.abi [32|64]'
     Specify the ABI for the following instructions.  Note that you
     cannot use this directive unless you specified an ABI on the
     command line, and the ABIs specified must match.

`.uaquad'
     Like .uaword and .ualong, this allows you to specify an
     intentionally unaligned quadword (64 bit word).



File: as.info,  Node: SH64 Opcodes,  Prev: SH64 Directives,  Up: SH64-Dependent

8.27.4 Opcodes
--------------

For detailed information on the SH64 machine instruction set, see
`SuperH 64 bit RISC Series Architecture Manual' (SuperH, Inc.).

   `as' implements all the standard SH64 opcodes.  In addition, the
following pseudo-opcodes may be expanded into one or more alternate
opcodes:

`movi'
     If the value doesn't fit into a standard `movi' opcode, `as' will
     replace the `movi' with a sequence of `movi' and `shori' opcodes.

`pt'
     This expands to a sequence of `movi' and `shori' opcode, followed
     by a `ptrel' opcode, or to a `pta' or `ptb' opcode, depending on
     the label referenced.



File: as.info,  Node: Sparc-Dependent,  Next: TIC54X-Dependent,  Prev: PPC-Dependent,  Up: Machine Dependencies

8.28 SPARC Dependent Features
=============================

* Menu:

* Sparc-Opts::                  Options
* Sparc-Aligned-Data::		Option to enforce aligned data
* Sparc-Float::                 Floating Point
* Sparc-Directives::            Sparc Machine Directives


File: as.info,  Node: Sparc-Opts,  Next: Sparc-Aligned-Data,  Up: Sparc-Dependent

8.28.1 Options
--------------

The SPARC chip family includes several successive levels, using the same
core instruction set, but including a few additional instructions at
each level.  There are exceptions to this however.  For details on what
instructions each variant supports, please see the chip's architecture
reference manual.

   By default, `as' assumes the core instruction set (SPARC v6), but
"bumps" the architecture level as needed: it switches to successively
higher architectures as it encounters instructions that only exist in
the higher levels.

   If not configured for SPARC v9 (`sparc64-*-*') GAS will not bump
passed sparclite by default, an option must be passed to enable the v9
instructions.

   GAS treats sparclite as being compatible with v8, unless an
architecture is explicitly requested.  SPARC v9 is always incompatible
with sparclite.

`-Av6 | -Av7 | -Av8 | -Asparclet | -Asparclite'
`-Av8plus | -Av8plusa | -Av9 | -Av9a'
     Use one of the `-A' options to select one of the SPARC
     architectures explicitly.  If you select an architecture
     explicitly, `as' reports a fatal error if it encounters an
     instruction or feature requiring an incompatible or higher level.

     `-Av8plus' and `-Av8plusa' select a 32 bit environment.

     `-Av9' and `-Av9a' select a 64 bit environment and are not
     available unless GAS is explicitly configured with 64 bit
     environment support.

     `-Av8plusa' and `-Av9a' enable the SPARC V9 instruction set with
     UltraSPARC extensions.

`-xarch=v8plus | -xarch=v8plusa'
     For compatibility with the Solaris v9 assembler.  These options are
     equivalent to -Av8plus and -Av8plusa, respectively.

`-bump'
     Warn whenever it is necessary to switch to another level.  If an
     architecture level is explicitly requested, GAS will not issue
     warnings until that level is reached, and will then bump the level
     as required (except between incompatible levels).

`-32 | -64'
     Select the word size, either 32 bits or 64 bits.  These options
     are only available with the ELF object file format, and require
     that the necessary BFD support has been included.


File: as.info,  Node: Sparc-Aligned-Data,  Next: Sparc-Float,  Prev: Sparc-Opts,  Up: Sparc-Dependent

8.28.2 Enforcing aligned data
-----------------------------

SPARC GAS normally permits data to be misaligned.  For example, it
permits the `.long' pseudo-op to be used on a byte boundary.  However,
the native SunOS and Solaris assemblers issue an error when they see
misaligned data.

   You can use the `--enforce-aligned-data' option to make SPARC GAS
also issue an error about misaligned data, just as the SunOS and Solaris
assemblers do.

   The `--enforce-aligned-data' option is not the default because gcc
issues misaligned data pseudo-ops when it initializes certain packed
data structures (structures defined using the `packed' attribute).  You
may have to assemble with GAS in order to initialize packed data
structures in your own code.


File: as.info,  Node: Sparc-Float,  Next: Sparc-Directives,  Prev: Sparc-Aligned-Data,  Up: Sparc-Dependent

8.28.3 Floating Point
---------------------

The Sparc uses IEEE floating-point numbers.


File: as.info,  Node: Sparc-Directives,  Prev: Sparc-Float,  Up: Sparc-Dependent

8.28.4 Sparc Machine Directives
-------------------------------

The Sparc version of `as' supports the following additional machine
directives:

`.align'
     This must be followed by the desired alignment in bytes.

`.common'
     This must be followed by a symbol name, a positive number, and
     `"bss"'.  This behaves somewhat like `.comm', but the syntax is
     different.

`.half'
     This is functionally identical to `.short'.

`.nword'
     On the Sparc, the `.nword' directive produces native word sized
     value, ie. if assembling with -32 it is equivalent to `.word', if
     assembling with -64 it is equivalent to `.xword'.

`.proc'
     This directive is ignored.  Any text following it on the same line
     is also ignored.

`.register'
     This directive declares use of a global application or system
     register.  It must be followed by a register name %g2, %g3, %g6 or
     %g7, comma and the symbol name for that register.  If symbol name
     is `#scratch', it is a scratch register, if it is `#ignore', it
     just suppresses any errors about using undeclared global register,
     but does not emit any information about it into the object file.
     This can be useful e.g. if you save the register before use and
     restore it after.

`.reserve'
     This must be followed by a symbol name, a positive number, and
     `"bss"'.  This behaves somewhat like `.lcomm', but the syntax is
     different.

`.seg'
     This must be followed by `"text"', `"data"', or `"data1"'.  It
     behaves like `.text', `.data', or `.data 1'.

`.skip'
     This is functionally identical to the `.space' directive.

`.word'
     On the Sparc, the `.word' directive produces 32 bit values,
     instead of the 16 bit values it produces on many other machines.

`.xword'
     On the Sparc V9 processor, the `.xword' directive produces 64 bit
     values.


File: as.info,  Node: TIC54X-Dependent,  Next: V850-Dependent,  Prev: Sparc-Dependent,  Up: Machine Dependencies

8.29 TIC54X Dependent Features
==============================

* Menu:

* TIC54X-Opts::              Command-line Options
* TIC54X-Block::             Blocking
* TIC54X-Env::               Environment Settings
* TIC54X-Constants::         Constants Syntax
* TIC54X-Subsyms::           String Substitution
* TIC54X-Locals::            Local Label Syntax
* TIC54X-Builtins::          Builtin Assembler Math Functions
* TIC54X-Ext::               Extended Addressing Support
* TIC54X-Directives::        Directives
* TIC54X-Macros::            Macro Features
* TIC54X-MMRegs::            Memory-mapped Registers


File: as.info,  Node: TIC54X-Opts,  Next: TIC54X-Block,  Up: TIC54X-Dependent

8.29.1 Options
--------------

The TMS320C54x version of `as' has a few machine-dependent options.

   You can use the `-mfar-mode' option to enable extended addressing
mode.  All addresses will be assumed to be > 16 bits, and the
appropriate relocation types will be used.  This option is equivalent
to using the `.far_mode' directive in the assembly code.  If you do not
use the `-mfar-mode' option, all references will be assumed to be 16
bits.  This option may be abbreviated to `-mf'.

   You can use the `-mcpu' option to specify a particular CPU.  This
option is equivalent to using the `.version' directive in the assembly
code.  For recognized CPU codes, see *Note `.version':
TIC54X-Directives.  The default CPU version is `542'.

   You can use the `-merrors-to-file' option to redirect error output
to a file (this provided for those deficient environments which don't
provide adequate output redirection).  This option may be abbreviated to
`-me'.


File: as.info,  Node: TIC54X-Block,  Next: TIC54X-Env,  Prev: TIC54X-Opts,  Up: TIC54X-Dependent

8.29.2 Blocking
---------------

A blocked section or memory block is guaranteed not to cross the
blocking boundary (usually a page, or 128 words) if it is smaller than
the blocking size, or to start on a page boundary if it is larger than
the blocking size.


File: as.info,  Node: TIC54X-Env,  Next: TIC54X-Constants,  Prev: TIC54X-Block,  Up: TIC54X-Dependent

8.29.3 Environment Settings
---------------------------

`C54XDSP_DIR' and `A_DIR' are semicolon-separated paths which are added
to the list of directories normally searched for source and include
files.  `C54XDSP_DIR' will override `A_DIR'.


File: as.info,  Node: TIC54X-Constants,  Next: TIC54X-Subsyms,  Prev: TIC54X-Env,  Up: TIC54X-Dependent

8.29.4 Constants Syntax
-----------------------

The TIC54X version of `as' allows the following additional constant
formats, using a suffix to indicate the radix:

     Binary                  `000000B, 011000b'
     Octal                   `10Q, 224q'
     Hexadecimal             `45h, 0FH'


File: as.info,  Node: TIC54X-Subsyms,  Next: TIC54X-Locals,  Prev: TIC54X-Constants,  Up: TIC54X-Dependent

8.29.5 String Substitution
--------------------------

A subset of allowable symbols (which we'll call subsyms) may be assigned
arbitrary string values.  This is roughly equivalent to C preprocessor
#define macros.  When `as' encounters one of these symbols, the symbol
is replaced in the input stream by its string value.  Subsym names
*must* begin with a letter.

   Subsyms may be defined using the `.asg' and `.eval' directives
(*Note `.asg': TIC54X-Directives, *Note `.eval': TIC54X-Directives.

   Expansion is recursive until a previously encountered symbol is
seen, at which point substitution stops.

   In this example, x is replaced with SYM2; SYM2 is replaced with
SYM1, and SYM1 is replaced with x.  At this point, x has already been
encountered and the substitution stops.

      .asg   "x",SYM1
      .asg   "SYM1",SYM2
      .asg   "SYM2",x
      add    x,a             ; final code assembled is "add  x, a"

   Macro parameters are converted to subsyms; a side effect of this is
the normal `as' '\ARG' dereferencing syntax is unnecessary.  Subsyms
defined within a macro will have global scope, unless the `.var'
directive is used to identify the subsym as a local macro variable
*note `.var': TIC54X-Directives.

   Substitution may be forced in situations where replacement might be
ambiguous by placing colons on either side of the subsym.  The following
code:

      .eval  "10",x
     LAB:X:  add     #x, a

   When assembled becomes:

     LAB10  add     #10, a

   Smaller parts of the string assigned to a subsym may be accessed with
the following syntax:

``:SYMBOL(CHAR_INDEX):''
     Evaluates to a single-character string, the character at
     CHAR_INDEX.

``:SYMBOL(START,LENGTH):''
     Evaluates to a substring of SYMBOL beginning at START with length
     LENGTH.


File: as.info,  Node: TIC54X-Locals,  Next: TIC54X-Builtins,  Prev: TIC54X-Subsyms,  Up: TIC54X-Dependent

8.29.6 Local Labels
-------------------

Local labels may be defined in two ways:

   * $N, where N is a decimal number between 0 and 9

   * LABEL?, where LABEL is any legal symbol name.

   Local labels thus defined may be redefined or automatically
generated.  The scope of a local label is based on when it may be
undefined or reset.  This happens when one of the following situations
is encountered:

   * .newblock directive *note `.newblock': TIC54X-Directives.

   * The current section is changed (.sect, .text, or .data)

   * Entering or leaving an included file

   * The macro scope where the label was defined is exited


File: as.info,  Node: TIC54X-Builtins,  Next: TIC54X-Ext,  Prev: TIC54X-Locals,  Up: TIC54X-Dependent

8.29.7 Math Builtins
--------------------

The following built-in functions may be used to generate a
floating-point value.  All return a floating-point value except `$cvi',
`$int', and `$sgn', which return an integer value.

``$acos(EXPR)''
     Returns the floating point arccosine of EXPR.

``$asin(EXPR)''
     Returns the floating point arcsine of EXPR.

``$atan(EXPR)''
     Returns the floating point arctangent of EXPR.

``$atan2(EXPR1,EXPR2)''
     Returns the floating point arctangent of EXPR1 / EXPR2.

``$ceil(EXPR)''
     Returns the smallest integer not less than EXPR as floating point.

``$cosh(EXPR)''
     Returns the floating point hyperbolic cosine of EXPR.

``$cos(EXPR)''
     Returns the floating point cosine of EXPR.

``$cvf(EXPR)''
     Returns the integer value EXPR converted to floating-point.

``$cvi(EXPR)''
     Returns the floating point value EXPR converted to integer.

``$exp(EXPR)''
     Returns the floating point value e ^ EXPR.

``$fabs(EXPR)''
     Returns the floating point absolute value of EXPR.

``$floor(EXPR)''
     Returns the largest integer that is not greater than EXPR as
     floating point.

``$fmod(EXPR1,EXPR2)''
     Returns the floating point remainder of EXPR1 / EXPR2.

``$int(EXPR)''
     Returns 1 if EXPR evaluates to an integer, zero otherwise.

``$ldexp(EXPR1,EXPR2)''
     Returns the floating point value EXPR1 * 2 ^ EXPR2.

``$log10(EXPR)''
     Returns the base 10 logarithm of EXPR.

``$log(EXPR)''
     Returns the natural logarithm of EXPR.

``$max(EXPR1,EXPR2)''
     Returns the floating point maximum of EXPR1 and EXPR2.

``$min(EXPR1,EXPR2)''
     Returns the floating point minimum of EXPR1 and EXPR2.

``$pow(EXPR1,EXPR2)''
     Returns the floating point value EXPR1 ^ EXPR2.

``$round(EXPR)''
     Returns the nearest integer to EXPR as a floating point number.

``$sgn(EXPR)''
     Returns -1, 0, or 1 based on the sign of EXPR.

``$sin(EXPR)''
     Returns the floating point sine of EXPR.

``$sinh(EXPR)''
     Returns the floating point hyperbolic sine of EXPR.

``$sqrt(EXPR)''
     Returns the floating point square root of EXPR.

``$tan(EXPR)''
     Returns the floating point tangent of EXPR.

``$tanh(EXPR)''
     Returns the floating point hyperbolic tangent of EXPR.

``$trunc(EXPR)''
     Returns the integer value of EXPR truncated towards zero as
     floating point.



File: as.info,  Node: TIC54X-Ext,  Next: TIC54X-Directives,  Prev: TIC54X-Builtins,  Up: TIC54X-Dependent

8.29.8 Extended Addressing
--------------------------

The `LDX' pseudo-op is provided for loading the extended addressing bits
of a label or address.  For example, if an address `_label' resides in
extended program memory, the value of `_label' may be loaded as follows:
      ldx     #_label,16,a    ; loads extended bits of _label
      or      #_label,a       ; loads lower 16 bits of _label
      bacc    a               ; full address is in accumulator A


File: as.info,  Node: TIC54X-Directives,  Next: TIC54X-Macros,  Prev: TIC54X-Ext,  Up: TIC54X-Dependent

8.29.9 Directives
-----------------

`.align [SIZE]'
`.even'
     Align the section program counter on the next boundary, based on
     SIZE.  SIZE may be any power of 2.  `.even' is equivalent to
     `.align' with a SIZE of 2.
    `1'
          Align SPC to word boundary

    `2'
          Align SPC to longword boundary (same as .even)

    `128'
          Align SPC to page boundary

`.asg STRING, NAME'
     Assign NAME the string STRING.  String replacement is performed on
     STRING before assignment.

`.eval STRING, NAME'
     Evaluate the contents of string STRING and assign the result as a
     string to the subsym NAME.  String replacement is performed on
     STRING before assignment.

`.bss SYMBOL, SIZE [, [BLOCKING_FLAG] [,ALIGNMENT_FLAG]]'
     Reserve space for SYMBOL in the .bss section.  SIZE is in words.
     If present, BLOCKING_FLAG indicates the allocated space should be
     aligned on a page boundary if it would otherwise cross a page
     boundary.  If present, ALIGNMENT_FLAG causes the assembler to
     allocate SIZE on a long word boundary.

`.byte VALUE [,...,VALUE_N]'
`.ubyte VALUE [,...,VALUE_N]'
`.char VALUE [,...,VALUE_N]'
`.uchar VALUE [,...,VALUE_N]'
     Place one or more bytes into consecutive words of the current
     section.  The upper 8 bits of each word is zero-filled.  If a
     label is used, it points to the word allocated for the first byte
     encountered.

`.clink ["SECTION_NAME"]'
     Set STYP_CLINK flag for this section, which indicates to the
     linker that if no symbols from this section are referenced, the
     section should not be included in the link.  If SECTION_NAME is
     omitted, the current section is used.

`.c_mode'
     TBD.

`.copy "FILENAME" | FILENAME'
`.include "FILENAME" | FILENAME'
     Read source statements from FILENAME.  The normal include search
     path is used.  Normally .copy will cause statements from the
     included file to be printed in the assembly listing and .include
     will not, but this distinction is not currently implemented.

`.data'
     Begin assembling code into the .data section.

`.double VALUE [,...,VALUE_N]'
`.ldouble VALUE [,...,VALUE_N]'
`.float VALUE [,...,VALUE_N]'
`.xfloat VALUE [,...,VALUE_N]'
     Place an IEEE single-precision floating-point representation of
     one or more floating-point values into the current section.  All
     but `.xfloat' align the result on a longword boundary.  Values are
     stored most-significant word first.

`.drlist'
`.drnolist'
     Control printing of directives to the listing file.  Ignored.

`.emsg STRING'
`.mmsg STRING'
`.wmsg STRING'
     Emit a user-defined error, message, or warning, respectively.

`.far_mode'
     Use extended addressing when assembling statements.  This should
     appear only once per file, and is equivalent to the -mfar-mode
     option *note `-mfar-mode': TIC54X-Opts.

`.fclist'
`.fcnolist'
     Control printing of false conditional blocks to the listing file.

`.field VALUE [,SIZE]'
     Initialize a bitfield of SIZE bits in the current section.  If
     VALUE is relocatable, then SIZE must be 16.  SIZE defaults to 16
     bits.  If VALUE does not fit into SIZE bits, the value will be
     truncated.  Successive `.field' directives will pack starting at
     the current word, filling the most significant bits first, and
     aligning to the start of the next word if the field size does not
     fit into the space remaining in the current word.  A `.align'
     directive with an operand of 1 will force the next `.field'
     directive to begin packing into a new word.  If a label is used, it
     points to the word that contains the specified field.

`.global SYMBOL [,...,SYMBOL_N]'
`.def SYMBOL [,...,SYMBOL_N]'
`.ref SYMBOL [,...,SYMBOL_N]'
     `.def' nominally identifies a symbol defined in the current file
     and availalbe to other files.  `.ref' identifies a symbol used in
     the current file but defined elsewhere.  Both map to the standard
     `.global' directive.

`.half VALUE [,...,VALUE_N]'
`.uhalf VALUE [,...,VALUE_N]'
`.short VALUE [,...,VALUE_N]'
`.ushort VALUE [,...,VALUE_N]'
`.int VALUE [,...,VALUE_N]'
`.uint VALUE [,...,VALUE_N]'
`.word VALUE [,...,VALUE_N]'
`.uword VALUE [,...,VALUE_N]'
     Place one or more values into consecutive words of the current
     section.  If a label is used, it points to the word allocated for
     the first value encountered.

`.label SYMBOL'
     Define a special SYMBOL to refer to the load time address of the
     current section program counter.

`.length'
`.width'
     Set the page length and width of the output listing file.  Ignored.

`.list'
`.nolist'
     Control whether the source listing is printed.  Ignored.

`.long VALUE [,...,VALUE_N]'
`.ulong VALUE [,...,VALUE_N]'
`.xlong VALUE [,...,VALUE_N]'
     Place one or more 32-bit values into consecutive words in the
     current section.  The most significant word is stored first.
     `.long' and `.ulong' align the result on a longword boundary;
     `xlong' does not.

`.loop [COUNT]'
`.break [CONDITION]'
`.endloop'
     Repeatedly assemble a block of code.  `.loop' begins the block, and
     `.endloop' marks its termination.  COUNT defaults to 1024, and
     indicates the number of times the block should be repeated.
     `.break' terminates the loop so that assembly begins after the
     `.endloop' directive.  The optional CONDITION will cause the loop
     to terminate only if it evaluates to zero.

`MACRO_NAME .macro [PARAM1][,...PARAM_N]'
`[.mexit]'
`.endm'
     See the section on macros for more explanation (*Note
     TIC54X-Macros::.

`.mlib "FILENAME" | FILENAME'
     Load the macro library FILENAME.  FILENAME must be an archived
     library (BFD ar-compatible) of text files, expected to contain
     only macro definitions.   The standard include search path is used.

`.mlist'

`.mnolist'
     Control whether to include macro and loop block expansions in the
     listing output.  Ignored.

`.mmregs'
     Define global symbolic names for the 'c54x registers.  Supposedly
     equivalent to executing `.set' directives for each register with
     its memory-mapped value, but in reality is provided only for
     compatibility and does nothing.

`.newblock'
     This directive resets any TIC54X local labels currently defined.
     Normal `as' local labels are unaffected.

`.option OPTION_LIST'
     Set listing options.  Ignored.

`.sblock "SECTION_NAME" | SECTION_NAME [,"NAME_N" | NAME_N]'
     Designate SECTION_NAME for blocking.  Blocking guarantees that a
     section will start on a page boundary (128 words) if it would
     otherwise cross a page boundary.  Only initialized sections may be
     designated with this directive.  See also *Note TIC54X-Block::.

`.sect "SECTION_NAME"'
     Define a named initialized section and make it the current section.

`SYMBOL .set "VALUE"'
`SYMBOL .equ "VALUE"'
     Equate a constant VALUE to a SYMBOL, which is placed in the symbol
     table.  SYMBOL may not be previously defined.

`.space SIZE_IN_BITS'
`.bes SIZE_IN_BITS'
     Reserve the given number of bits in the current section and
     zero-fill them.  If a label is used with `.space', it points to the
     *first* word reserved.  With `.bes', the label points to the
     *last* word reserved.

`.sslist'
`.ssnolist'
     Controls the inclusion of subsym replacement in the listing
     output.  Ignored.

`.string "STRING" [,...,"STRING_N"]'
`.pstring "STRING" [,...,"STRING_N"]'
     Place 8-bit characters from STRING into the current section.
     `.string' zero-fills the upper 8 bits of each word, while
     `.pstring' puts two characters into each word, filling the
     most-significant bits first.  Unused space is zero-filled.  If a
     label is used, it points to the first word initialized.

`[STAG] .struct [OFFSET]'
`[NAME_1] element [COUNT_1]'
`[NAME_2] element [COUNT_2]'
`[TNAME] .tag STAGX [TCOUNT]'
`...'
`[NAME_N] element [COUNT_N]'
`[SSIZE] .endstruct'
`LABEL .tag [STAG]'
     Assign symbolic offsets to the elements of a structure.  STAG
     defines a symbol to use to reference the structure.  OFFSET
     indicates a starting value to use for the first element
     encountered; otherwise it defaults to zero.  Each element can have
     a named offset, NAME, which is a symbol assigned the value of the
     element's offset into the structure.  If STAG is missing, these
     become global symbols.  COUNT adjusts the offset that many times,
     as if `element' were an array.  `element' may be one of `.byte',
     `.word', `.long', `.float', or any equivalent of those, and the
     structure offset is adjusted accordingly.  `.field' and `.string'
     are also allowed; the size of `.field' is one bit, and `.string'
     is considered to be one word in size.  Only element descriptors,
     structure/union tags, `.align' and conditional assembly directives
     are allowed within `.struct'/`.endstruct'.  `.align' aligns member
     offsets to word boundaries only.  SSIZE, if provided, will always
     be assigned the size of the structure.

     The `.tag' directive, in addition to being used to define a
     structure/union element within a structure, may be used to apply a
     structure to a symbol.  Once applied to LABEL, the individual
     structure elements may be applied to LABEL to produce the desired
     offsets using LABEL as the structure base.

`.tab'
     Set the tab size in the output listing.  Ignored.

`[UTAG] .union'
`[NAME_1] element [COUNT_1]'
`[NAME_2] element [COUNT_2]'
`[TNAME] .tag UTAGX[,TCOUNT]'
`...'
`[NAME_N] element [COUNT_N]'
`[USIZE] .endstruct'
`LABEL .tag [UTAG]'
     Similar to `.struct', but the offset after each element is reset to
     zero, and the USIZE is set to the maximum of all defined elements.
     Starting offset for the union is always zero.

`[SYMBOL] .usect "SECTION_NAME", SIZE, [,[BLOCKING_FLAG] [,ALIGNMENT_FLAG]]'
     Reserve space for variables in a named, uninitialized section
     (similar to .bss).  `.usect' allows definitions sections
     independent of .bss.  SYMBOL points to the first location reserved
     by this allocation.  The symbol may be used as a variable name.
     SIZE is the allocated size in words.  BLOCKING_FLAG indicates
     whether to block this section on a page boundary (128 words)
     (*note TIC54X-Block::).  ALIGNMENT FLAG indicates whether the
     section should be longword-aligned.

`.var SYM[,..., SYM_N]'
     Define a subsym to be a local variable within a macro.  See *Note
     TIC54X-Macros::.

`.version VERSION'
     Set which processor to build instructions for.  Though the
     following values are accepted, the op is ignored.
    `541'
    `542'
    `543'
    `545'
    `545LP'
    `546LP'
    `548'
    `549'


File: as.info,  Node: TIC54X-Macros,  Next: TIC54X-MMRegs,  Prev: TIC54X-Directives,  Up: TIC54X-Dependent

8.29.10 Macros
--------------

Macros do not require explicit dereferencing of arguments (i.e. \ARG).

   During macro expansion, the macro parameters are converted to
subsyms.  If the number of arguments passed the macro invocation
exceeds the number of parameters defined, the last parameter is
assigned the string equivalent of all remaining arguments.  If fewer
arguments are given than parameters, the missing parameters are
assigned empty strings.  To include a comma in an argument, you must
enclose the argument in quotes.

   The following built-in subsym functions allow examination of the
string value of subsyms (or ordinary strings).  The arguments are
strings unless otherwise indicated (subsyms passed as args will be
replaced by the strings they represent).
``$symlen(STR)''
     Returns the length of STR.

``$symcmp(STR1,STR2)''
     Returns 0 if STR1 == STR2, non-zero otherwise.

``$firstch(STR,CH)''
     Returns index of the first occurrence of character constant CH in
     STR.

``$lastch(STR,CH)''
     Returns index of the last occurrence of character constant CH in
     STR.

``$isdefed(SYMBOL)''
     Returns zero if the symbol SYMBOL is not in the symbol table,
     non-zero otherwise.

``$ismember(SYMBOL,LIST)''
     Assign the first member of comma-separated string LIST to SYMBOL;
     LIST is reassigned the remainder of the list.  Returns zero if
     LIST is a null string.  Both arguments must be subsyms.

``$iscons(EXPR)''
     Returns 1 if string EXPR is binary, 2 if octal, 3 if hexadecimal,
     4 if a character, 5 if decimal, and zero if not an integer.

``$isname(NAME)''
     Returns 1 if NAME is a valid symbol name, zero otherwise.

``$isreg(REG)''
     Returns 1 if REG is a valid predefined register name (AR0-AR7
     only).

``$structsz(STAG)''
     Returns the size of the structure or union represented by STAG.

``$structacc(STAG)''
     Returns the reference point of the structure or union represented
     by STAG.   Always returns zero.



File: as.info,  Node: TIC54X-MMRegs,  Prev: TIC54X-Macros,  Up: TIC54X-Dependent

8.29.11 Memory-mapped Registers
-------------------------------

The following symbols are recognized as memory-mapped registers:



File: as.info,  Node: Z80-Dependent,  Next: Z8000-Dependent,  Prev: Xtensa-Dependent,  Up: Machine Dependencies

8.30 Z80 Dependent Features
===========================

* Menu:

* Z80 Options::              Options
* Z80 Syntax::               Syntax
* Z80 Floating Point::       Floating Point
* Z80 Directives::           Z80 Machine Directives
* Z80 Opcodes::              Opcodes


File: as.info,  Node: Z80 Options,  Next: Z80 Syntax,  Up: Z80-Dependent

8.30.1 Options
--------------

The Zilog Z80 and Ascii R800 version of `as' have a few machine
dependent options.
`-z80'
     Produce code for the Z80 processor. There are additional options to
     request warnings and error messages for undocumented instructions.

`-ignore-undocumented-instructions'
`-Wnud'
     Silently assemble undocumented Z80-instructions that have been
     adopted as documented R800-instructions.

`-ignore-unportable-instructions'
`-Wnup'
     Silently assemble all undocumented Z80-instructions.

`-warn-undocumented-instructions'
`-Wud'
     Issue warnings for undocumented Z80-instructions that work on
     R800, do not assemble other undocumented instructions without
     warning.

`-warn-unportable-instructions'
`-Wup'
     Issue warnings for other undocumented Z80-instructions, do not
     treat any undocumented instructions as errors.

`-forbid-undocumented-instructions'
`-Fud'
     Treat all undocumented z80-instructions as errors.

`-forbid-unportable-instructions'
`-Fup'
     Treat undocumented z80-instructions that do not work on R800 as
     errors.

`-r800'
     Produce code for the R800 processor. The assembler does not support
     undocumented instructions for the R800.  In line with common
     practice, `as' uses Z80 instriction names for the R800 processor,
     as far as they exist.


File: as.info,  Node: Z80 Syntax,  Next: Z80 Floating Point,  Prev: Z80 Options,  Up: Z80-Dependent

8.30.2 Syntax
-------------

The assembler syntax closely follows the 'Z80 family CPU User Manual' by
Zilog.  In expressions a single `=' may be used as "is equal to"
comparison operator.

   Suffices can be used to indicate the radix of integer constants; `H'
or `h' for hexadecimal, `D' or `d' for decimal, `Q', `O', `q' or `o'
for octal, and `B' for binary.

   The suffix `b' denotes a backreference to local label.

* Menu:

* Z80-Chars::                Special Characters
* Z80-Regs::                 Register Names
* Z80-Case::                 Case Sensitivity


File: as.info,  Node: Z80-Chars,  Next: Z80-Regs,  Up: Z80 Syntax

8.30.2.1 Special Characters
...........................

The semicolon `;' is the line comment character;

   The dollar sign `$' can be used as a prefix for hexadecimal numbers
and as a symbol denoting the current location counter.

   A backslash `\' is an ordinary character for the Z80 assembler.

   The single quote `'' must be followed by a closing quote. If there
is one character inbetween, it is a character constant, otherwise it is
a string constant.


File: as.info,  Node: Z80-Regs,  Next: Z80-Case,  Prev: Z80-Chars,  Up: Z80 Syntax

8.30.2.2 Register Names
.......................

The registers are referred to with the letters assigned to them by
Zilog. In addition `as' recognises `ixl' and `ixh' as the least and
most significant octet in `ix', and similarly `iyl' and  `iyh' as parts
of `iy'.


File: as.info,  Node: Z80-Case,  Prev: Z80-Regs,  Up: Z80 Syntax

8.30.2.3 Case Sensitivity
.........................

Upper and lower case are equivalent in register names, opcodes,
condition codes  and assembler directives.  The case of letters is
significant in labels and symbol names. The case is also important to
distinguish the suffix `b' for a backward reference to a local label
from the suffix `B' for a number in binary notation.


File: as.info,  Node: Z80 Floating Point,  Next: Z80 Directives,  Prev: Z80 Syntax,  Up: Z80-Dependent

8.30.3 Floating Point
---------------------

Floating-point numbers are not supported.


File: as.info,  Node: Z80 Directives,  Next: Z80 Opcodes,  Prev: Z80 Floating Point,  Up: Z80-Dependent

8.30.4 Z80 Assembler Directives
-------------------------------

`as' for the Z80 supports some additional directives for compatibility
with other assemblers.

   These are the additional directives in `as' for the Z80:

`db EXPRESSION|STRING[,EXPRESSION|STRING...]'
`defb EXPRESSION|STRING[,EXPRESSION|STRING...]'
     For each STRING the characters are copied to the object file, for
     each other EXPRESSION the value is stored in one byte.  A warning
     is issued in case of an overflow.

`dw EXPRESSION[,EXPRESSION...]'
`defw EXPRESSION[,EXPRESSION...]'
     For each EXPRESSION the value is stored in two bytes, ignoring
     overflow.

`d24 EXPRESSION[,EXPRESSION...]'
`def24 EXPRESSION[,EXPRESSION...]'
     For each EXPRESSION the value is stored in three bytes, ignoring
     overflow.

`d32 EXPRESSION[,EXPRESSION...]'
`def32 EXPRESSION[,EXPRESSION...]'
     For each EXPRESSION the value is stored in four bytes, ignoring
     overflow.

`ds COUNT[, VALUE]'
`defs COUNT[, VALUE]'
     Fill COUNT bytes in the object file with VALUE, if VALUE is
     omitted it defaults to zero.

`SYMBOL equ EXPRESSION'
`SYMBOL defl EXPRESSION'
     These directives set the value of SYMBOL to EXPRESSION. If `equ'
     is used, it is an error if SYMBOL is already defined.  Symbols
     defined with `equ' are not protected from redefinition.

`set'
     This is a normal instruction on Z80, and not an assembler
     directive.

`psect NAME'
     A synonym for *Note Section::, no second argument should be given.



File: as.info,  Node: Z80 Opcodes,  Prev: Z80 Directives,  Up: Z80-Dependent

8.30.5 Opcodes
--------------

In line with commmon practice Z80 mnonics are used for both the Z80 and
the R800.

   In many instructions it is possible to use one of the half index
registers (`ixl',`ixh',`iyl',`iyh') in stead of an 8-bit general
purpose register. This yields instructions that are documented on the
R800 and undocumented on the Z80.  Similarly `in f,(c)' is documented
on the R800 and undocumented on the Z80.

   The assembler also supports the following undocumented
Z80-instructions, that have not been adopted in the R800 instruction
set:
`out (c),0'
     Sends zero to the port pointed to by register c.

`sli M'
     Equivalent to `M = (M<<1)+1', the operand M can be any operand
     that is valid for `sla'. One can use `sll' as a synonym for `sli'.

`OP (ix+D), R'
     This is equivalent to

          ld R, (ix+D)
          OPC R
          ld (ix+D), R

     The operation `OPC' may be any of `res B,', `set B,', `rl', `rlc',
     `rr', `rrc', `sla', `sli', `sra' and `srl', and the register `R'
     may be any of `a', `b', `c', `d', `e', `h' and `l'.

`OPC (iy+D), R'
     As above, but with `iy' instead of `ix'.

   The web site at `http://www.z80.info' is a good starting place to
find more information on programming the Z80.


File: as.info,  Node: Z8000-Dependent,  Next: Vax-Dependent,  Prev: Z80-Dependent,  Up: Machine Dependencies

8.31 Z8000 Dependent Features
=============================

   The Z8000 as supports both members of the Z8000 family: the
unsegmented Z8002, with 16 bit addresses, and the segmented Z8001 with
24 bit addresses.

   When the assembler is in unsegmented mode (specified with the
`unsegm' directive), an address takes up one word (16 bit) sized
register.  When the assembler is in segmented mode (specified with the
`segm' directive), a 24-bit address takes up a long (32 bit) register.
*Note Assembler Directives for the Z8000: Z8000 Directives, for a list
of other Z8000 specific assembler directives.

* Menu:

* Z8000 Options::               Command-line options for the Z8000
* Z8000 Syntax::                Assembler syntax for the Z8000
* Z8000 Directives::            Special directives for the Z8000
* Z8000 Opcodes::               Opcodes


File: as.info,  Node: Z8000 Options,  Next: Z8000 Syntax,  Up: Z8000-Dependent

8.31.1 Options
--------------

`-z8001'
     Generate segmented code by default.

`-z8002'
     Generate unsegmented code by default.


File: as.info,  Node: Z8000 Syntax,  Next: Z8000 Directives,  Prev: Z8000 Options,  Up: Z8000-Dependent

8.31.2 Syntax
-------------

* Menu:

* Z8000-Chars::                Special Characters
* Z8000-Regs::                 Register Names
* Z8000-Addressing::           Addressing Modes


File: as.info,  Node: Z8000-Chars,  Next: Z8000-Regs,  Up: Z8000 Syntax

8.31.2.1 Special Characters
...........................

`!' is the line comment character.

   You can use `;' instead of a newline to separate statements.


File: as.info,  Node: Z8000-Regs,  Next: Z8000-Addressing,  Prev: Z8000-Chars,  Up: Z8000 Syntax

8.31.2.2 Register Names
.......................

The Z8000 has sixteen 16 bit registers, numbered 0 to 15.  You can refer
to different sized groups of registers by register number, with the
prefix `r' for 16 bit registers, `rr' for 32 bit registers and `rq' for
64 bit registers.  You can also refer to the contents of the first
eight (of the sixteen 16 bit registers) by bytes.  They are named `rlN'
and `rhN'.

_byte registers_
     rl0 rh0 rl1 rh1 rl2 rh2 rl3 rh3
     rl4 rh4 rl5 rh5 rl6 rh6 rl7 rh7

_word registers_
     r0 r1 r2 r3 r4 r5 r6 r7 r8 r9 r10 r11 r12 r13 r14 r15

_long word registers_
     rr0 rr2 rr4 rr6 rr8 rr10 rr12 rr14

_quad word registers_
     rq0 rq4 rq8 rq12


File: as.info,  Node: Z8000-Addressing,  Prev: Z8000-Regs,  Up: Z8000 Syntax

8.31.2.3 Addressing Modes
.........................

as understands the following addressing modes for the Z8000:

`rlN'
`rhN'
`rN'
`rrN'
`rqN'
     Register direct:  8bit, 16bit, 32bit, and 64bit registers.

`@rN'
`@rrN'
     Indirect register:  @rrN in segmented mode, @rN in unsegmented
     mode.

`ADDR'
     Direct: the 16 bit or 24 bit address (depending on whether the
     assembler is in segmented or unsegmented mode) of the operand is
     in the instruction.

`address(rN)'
     Indexed: the 16 or 24 bit address is added to the 16 bit register
     to produce the final address in memory of the operand.

`rN(#IMM)'
`rrN(#IMM)'
     Base Address: the 16 or 24 bit register is added to the 16 bit sign
     extended immediate displacement to produce the final address in
     memory of the operand.

`rN(rM)'
`rrN(rM)'
     Base Index: the 16 or 24 bit register rN or rrN is added to the
     sign extended 16 bit index register rM to produce the final
     address in memory of the operand.

`#XX'
     Immediate data XX.


File: as.info,  Node: Z8000 Directives,  Next: Z8000 Opcodes,  Prev: Z8000 Syntax,  Up: Z8000-Dependent

8.31.3 Assembler Directives for the Z8000
-----------------------------------------

The Z8000 port of as includes additional assembler directives, for
compatibility with other Z8000 assemblers.  These do not begin with `.'
(unlike the ordinary as directives).

`segm'
`.z8001'
     Generate code for the segmented Z8001.

`unsegm'
`.z8002'
     Generate code for the unsegmented Z8002.

`name'
     Synonym for `.file'

`global'
     Synonym for `.global'

`wval'
     Synonym for `.word'

`lval'
     Synonym for `.long'

`bval'
     Synonym for `.byte'

`sval'
     Assemble a string.  `sval' expects one string literal, delimited by
     single quotes.  It assembles each byte of the string into
     consecutive addresses.  You can use the escape sequence `%XX'
     (where XX represents a two-digit hexadecimal number) to represent
     the character whose ASCII value is XX.  Use this feature to
     describe single quote and other characters that may not appear in
     string literals as themselves.  For example, the C statement
     `char *a = "he said \"it's 50% off\"";' is represented in Z8000
     assembly language (shown with the assembler output in hex at the
     left) as

          68652073    sval    'he said %22it%27s 50%25 off%22%00'
          61696420
          22697427
          73203530
          25206F66
          662200

`rsect'
     synonym for `.section'

`block'
     synonym for `.space'

`even'
     special case of `.align'; aligns output to even byte boundary.


File: as.info,  Node: Z8000 Opcodes,  Prev: Z8000 Directives,  Up: Z8000-Dependent

8.31.4 Opcodes
--------------

For detailed information on the Z8000 machine instruction set, see
`Z8000 Technical Manual'.

   The following table summarizes the opcodes and their arguments:

                 rs   16 bit source register
                 rd   16 bit destination register
                 rbs   8 bit source register
                 rbd   8 bit destination register
                 rrs   32 bit source register
                 rrd   32 bit destination register
                 rqs   64 bit source register
                 rqd   64 bit destination register
                 addr 16/24 bit address
                 imm  immediate data

     adc rd,rs               clrb addr               cpsir @rd,@rs,rr,cc
     adcb rbd,rbs            clrb addr(rd)           cpsirb @rd,@rs,rr,cc
     add rd,@rs              clrb rbd                dab rbd
     add rd,addr             com @rd                 dbjnz rbd,disp7
     add rd,addr(rs)         com addr                dec @rd,imm4m1
     add rd,imm16            com addr(rd)            dec addr(rd),imm4m1
     add rd,rs               com rd                  dec addr,imm4m1
     addb rbd,@rs            comb @rd                dec rd,imm4m1
     addb rbd,addr           comb addr               decb @rd,imm4m1
     addb rbd,addr(rs)       comb addr(rd)           decb addr(rd),imm4m1
     addb rbd,imm8           comb rbd                decb addr,imm4m1
     addb rbd,rbs            comflg flags            decb rbd,imm4m1
     addl rrd,@rs            cp @rd,imm16            di i2
     addl rrd,addr           cp addr(rd),imm16       div rrd,@rs
     addl rrd,addr(rs)       cp addr,imm16           div rrd,addr
     addl rrd,imm32          cp rd,@rs               div rrd,addr(rs)
     addl rrd,rrs            cp rd,addr              div rrd,imm16
     and rd,@rs              cp rd,addr(rs)          div rrd,rs
     and rd,addr             cp rd,imm16             divl rqd,@rs
     and rd,addr(rs)         cp rd,rs                divl rqd,addr
     and rd,imm16            cpb @rd,imm8            divl rqd,addr(rs)
     and rd,rs               cpb addr(rd),imm8       divl rqd,imm32
     andb rbd,@rs            cpb addr,imm8           divl rqd,rrs
     andb rbd,addr           cpb rbd,@rs             djnz rd,disp7
     andb rbd,addr(rs)       cpb rbd,addr            ei i2
     andb rbd,imm8           cpb rbd,addr(rs)        ex rd,@rs
     andb rbd,rbs            cpb rbd,imm8            ex rd,addr
     bit @rd,imm4            cpb rbd,rbs             ex rd,addr(rs)
     bit addr(rd),imm4       cpd rd,@rs,rr,cc        ex rd,rs
     bit addr,imm4           cpdb rbd,@rs,rr,cc      exb rbd,@rs
     bit rd,imm4             cpdr rd,@rs,rr,cc       exb rbd,addr
     bit rd,rs               cpdrb rbd,@rs,rr,cc     exb rbd,addr(rs)
     bitb @rd,imm4           cpi rd,@rs,rr,cc        exb rbd,rbs
     bitb addr(rd),imm4      cpib rbd,@rs,rr,cc      ext0e imm8
     bitb addr,imm4          cpir rd,@rs,rr,cc       ext0f imm8
     bitb rbd,imm4           cpirb rbd,@rs,rr,cc     ext8e imm8
     bitb rbd,rs             cpl rrd,@rs             ext8f imm8
     bpt                     cpl rrd,addr            exts rrd
     call @rd                cpl rrd,addr(rs)        extsb rd
     call addr               cpl rrd,imm32           extsl rqd
     call addr(rd)           cpl rrd,rrs             halt
     calr disp12             cpsd @rd,@rs,rr,cc      in rd,@rs
     clr @rd                 cpsdb @rd,@rs,rr,cc     in rd,imm16
     clr addr                cpsdr @rd,@rs,rr,cc     inb rbd,@rs
     clr addr(rd)            cpsdrb @rd,@rs,rr,cc    inb rbd,imm16
     clr rd                  cpsi @rd,@rs,rr,cc      inc @rd,imm4m1
     clrb @rd                cpsib @rd,@rs,rr,cc     inc addr(rd),imm4m1
     inc addr,imm4m1         ldb rbd,rs(rx)          mult rrd,addr(rs)
     inc rd,imm4m1           ldb rd(imm16),rbs       mult rrd,imm16
     incb @rd,imm4m1         ldb rd(rx),rbs          mult rrd,rs
     incb addr(rd),imm4m1    ldctl ctrl,rs           multl rqd,@rs
     incb addr,imm4m1        ldctl rd,ctrl           multl rqd,addr
     incb rbd,imm4m1         ldd @rs,@rd,rr          multl rqd,addr(rs)
     ind @rd,@rs,ra          lddb @rs,@rd,rr         multl rqd,imm32
     indb @rd,@rs,rba        lddr @rs,@rd,rr         multl rqd,rrs
     inib @rd,@rs,ra         lddrb @rs,@rd,rr        neg @rd
     inibr @rd,@rs,ra        ldi @rd,@rs,rr          neg addr
     iret                    ldib @rd,@rs,rr         neg addr(rd)
     jp cc,@rd               ldir @rd,@rs,rr         neg rd
     jp cc,addr              ldirb @rd,@rs,rr        negb @rd
     jp cc,addr(rd)          ldk rd,imm4             negb addr
     jr cc,disp8             ldl @rd,rrs             negb addr(rd)
     ld @rd,imm16            ldl addr(rd),rrs        negb rbd
     ld @rd,rs               ldl addr,rrs            nop
     ld addr(rd),imm16       ldl rd(imm16),rrs       or rd,@rs
     ld addr(rd),rs          ldl rd(rx),rrs          or rd,addr
     ld addr,imm16           ldl rrd,@rs             or rd,addr(rs)
     ld addr,rs              ldl rrd,addr            or rd,imm16
     ld rd(imm16),rs         ldl rrd,addr(rs)        or rd,rs
     ld rd(rx),rs            ldl rrd,imm32           orb rbd,@rs
     ld rd,@rs               ldl rrd,rrs             orb rbd,addr
     ld rd,addr              ldl rrd,rs(imm16)       orb rbd,addr(rs)
     ld rd,addr(rs)          ldl rrd,rs(rx)          orb rbd,imm8
     ld rd,imm16             ldm @rd,rs,n            orb rbd,rbs
     ld rd,rs                ldm addr(rd),rs,n       out @rd,rs
     ld rd,rs(imm16)         ldm addr,rs,n           out imm16,rs
     ld rd,rs(rx)            ldm rd,@rs,n            outb @rd,rbs
     lda rd,addr             ldm rd,addr(rs),n       outb imm16,rbs
     lda rd,addr(rs)         ldm rd,addr,n           outd @rd,@rs,ra
     lda rd,rs(imm16)        ldps @rs                outdb @rd,@rs,rba
     lda rd,rs(rx)           ldps addr               outib @rd,@rs,ra
     ldar rd,disp16          ldps addr(rs)           outibr @rd,@rs,ra
     ldb @rd,imm8            ldr disp16,rs           pop @rd,@rs
     ldb @rd,rbs             ldr rd,disp16           pop addr(rd),@rs
     ldb addr(rd),imm8       ldrb disp16,rbs         pop addr,@rs
     ldb addr(rd),rbs        ldrb rbd,disp16         pop rd,@rs
     ldb addr,imm8           ldrl disp16,rrs         popl @rd,@rs
     ldb addr,rbs            ldrl rrd,disp16         popl addr(rd),@rs
     ldb rbd,@rs             mbit                    popl addr,@rs
     ldb rbd,addr            mreq rd                 popl rrd,@rs
     ldb rbd,addr(rs)        mres                    push @rd,@rs
     ldb rbd,imm8            mset                    push @rd,addr
     ldb rbd,rbs             mult rrd,@rs            push @rd,addr(rs)
     ldb rbd,rs(imm16)       mult rrd,addr           push @rd,imm16
     push @rd,rs             set addr,imm4           subl rrd,imm32
     pushl @rd,@rs           set rd,imm4             subl rrd,rrs
     pushl @rd,addr          set rd,rs               tcc cc,rd
     pushl @rd,addr(rs)      setb @rd,imm4           tccb cc,rbd
     pushl @rd,rrs           setb addr(rd),imm4      test @rd
     res @rd,imm4            setb addr,imm4          test addr
     res addr(rd),imm4       setb rbd,imm4           test addr(rd)
     res addr,imm4           setb rbd,rs             test rd
     res rd,imm4             setflg imm4             testb @rd
     res rd,rs               sinb rbd,imm16          testb addr
     resb @rd,imm4           sinb rd,imm16           testb addr(rd)
     resb addr(rd),imm4      sind @rd,@rs,ra         testb rbd
     resb addr,imm4          sindb @rd,@rs,rba       testl @rd
     resb rbd,imm4           sinib @rd,@rs,ra        testl addr
     resb rbd,rs             sinibr @rd,@rs,ra       testl addr(rd)
     resflg imm4             sla rd,imm8             testl rrd
     ret cc                  slab rbd,imm8           trdb @rd,@rs,rba
     rl rd,imm1or2           slal rrd,imm8           trdrb @rd,@rs,rba
     rlb rbd,imm1or2         sll rd,imm8             trib @rd,@rs,rbr
     rlc rd,imm1or2          sllb rbd,imm8           trirb @rd,@rs,rbr
     rlcb rbd,imm1or2        slll rrd,imm8           trtdrb @ra,@rb,rbr
     rldb rbb,rba            sout imm16,rs           trtib @ra,@rb,rr
     rr rd,imm1or2           soutb imm16,rbs         trtirb @ra,@rb,rbr
     rrb rbd,imm1or2         soutd @rd,@rs,ra        trtrb @ra,@rb,rbr
     rrc rd,imm1or2          soutdb @rd,@rs,rba      tset @rd
     rrcb rbd,imm1or2        soutib @rd,@rs,ra       tset addr
     rrdb rbb,rba            soutibr @rd,@rs,ra      tset addr(rd)
     rsvd36                  sra rd,imm8             tset rd
     rsvd38                  srab rbd,imm8           tsetb @rd
     rsvd78                  sral rrd,imm8           tsetb addr
     rsvd7e                  srl rd,imm8             tsetb addr(rd)
     rsvd9d                  srlb rbd,imm8           tsetb rbd
     rsvd9f                  srll rrd,imm8           xor rd,@rs
     rsvdb9                  sub rd,@rs              xor rd,addr
     rsvdbf                  sub rd,addr             xor rd,addr(rs)
     sbc rd,rs               sub rd,addr(rs)         xor rd,imm16
     sbcb rbd,rbs            sub rd,imm16            xor rd,rs
     sc imm8                 sub rd,rs               xorb rbd,@rs
     sda rd,rs               subb rbd,@rs            xorb rbd,addr
     sdab rbd,rs             subb rbd,addr           xorb rbd,addr(rs)
     sdal rrd,rs             subb rbd,addr(rs)       xorb rbd,imm8
     sdl rd,rs               subb rbd,imm8           xorb rbd,rbs
     sdlb rbd,rs             subb rbd,rbs            xorb rbd,rbs
     sdll rrd,rs             subl rrd,@rs
     set @rd,imm4            subl rrd,addr
     set addr(rd),imm4       subl rrd,addr(rs)


File: as.info,  Node: Vax-Dependent,  Prev: Z8000-Dependent,  Up: Machine Dependencies

8.32 VAX Dependent Features
===========================

* Menu:

* VAX-Opts::                    VAX Command-Line Options
* VAX-float::                   VAX Floating Point
* VAX-directives::              Vax Machine Directives
* VAX-opcodes::                 VAX Opcodes
* VAX-branch::                  VAX Branch Improvement
* VAX-operands::                VAX Operands
* VAX-no::                      Not Supported on VAX


File: as.info,  Node: VAX-Opts,  Next: VAX-float,  Up: Vax-Dependent

8.32.1 VAX Command-Line Options
-------------------------------

The Vax version of `as' accepts any of the following options, gives a
warning message that the option was ignored and proceeds.  These
options are for compatibility with scripts designed for other people's
assemblers.

``-D' (Debug)'
``-S' (Symbol Table)'
``-T' (Token Trace)'
     These are obsolete options used to debug old assemblers.

``-d' (Displacement size for JUMPs)'
     This option expects a number following the `-d'.  Like options
     that expect filenames, the number may immediately follow the `-d'
     (old standard) or constitute the whole of the command line
     argument that follows `-d' (GNU standard).

``-V' (Virtualize Interpass Temporary File)'
     Some other assemblers use a temporary file.  This option commanded
     them to keep the information in active memory rather than in a
     disk file.  `as' always does this, so this option is redundant.

``-J' (JUMPify Longer Branches)'
     Many 32-bit computers permit a variety of branch instructions to
     do the same job.  Some of these instructions are short (and fast)
     but have a limited range; others are long (and slow) but can
     branch anywhere in virtual memory.  Often there are 3 flavors of
     branch: short, medium and long.  Some other assemblers would emit
     short and medium branches, unless told by this option to emit
     short and long branches.

``-t' (Temporary File Directory)'
     Some other assemblers may use a temporary file, and this option
     takes a filename being the directory to site the temporary file.
     Since `as' does not use a temporary disk file, this option makes
     no difference.  `-t' needs exactly one filename.

   The Vax version of the assembler accepts additional options when
compiled for VMS:

`-h N'
     External symbol or section (used for global variables) names are
     not case sensitive on VAX/VMS and always mapped to upper case.
     This is contrary to the C language definition which explicitly
     distinguishes upper and lower case.  To implement a standard
     conforming C compiler, names must be changed (mapped) to preserve
     the case information.  The default mapping is to convert all lower
     case characters to uppercase and adding an underscore followed by
     a 6 digit hex value, representing a 24 digit binary value.  The
     one digits in the binary value represent which characters are
     uppercase in the original symbol name.

     The `-h N' option determines how we map names.  This takes several
     values.  No `-h' switch at all allows case hacking as described
     above.  A value of zero (`-h0') implies names should be upper
     case, and inhibits the case hack.  A value of 2 (`-h2') implies
     names should be all lower case, with no case hack.  A value of 3
     (`-h3') implies that case should be preserved.  The value 1 is
     unused.  The `-H' option directs `as' to display every mapped
     symbol during assembly.

     Symbols whose names include a dollar sign `$' are exceptions to the
     general name mapping.  These symbols are normally only used to
     reference VMS library names.  Such symbols are always mapped to
     upper case.

`-+'
     The `-+' option causes `as' to truncate any symbol name larger
     than 31 characters.  The `-+' option also prevents some code
     following the `_main' symbol normally added to make the object
     file compatible with Vax-11 "C".

`-1'
     This option is ignored for backward compatibility with `as'
     version 1.x.

`-H'
     The `-H' option causes `as' to print every symbol which was
     changed by case mapping.


File: as.info,  Node: VAX-float,  Next: VAX-directives,  Prev: VAX-Opts,  Up: Vax-Dependent

8.32.2 VAX Floating Point
-------------------------

Conversion of flonums to floating point is correct, and compatible with
previous assemblers.  Rounding is towards zero if the remainder is
exactly half the least significant bit.

   `D', `F', `G' and `H' floating point formats are understood.

   Immediate floating literals (_e.g._ `S`$6.9') are rendered
correctly.  Again, rounding is towards zero in the boundary case.

   The `.float' directive produces `f' format numbers.  The `.double'
directive produces `d' format numbers.


File: as.info,  Node: VAX-directives,  Next: VAX-opcodes,  Prev: VAX-float,  Up: Vax-Dependent

8.32.3 Vax Machine Directives
-----------------------------

The Vax version of the assembler supports four directives for
generating Vax floating point constants.  They are described in the
table below.

`.dfloat'
     This expects zero or more flonums, separated by commas, and
     assembles Vax `d' format 64-bit floating point constants.

`.ffloat'
     This expects zero or more flonums, separated by commas, and
     assembles Vax `f' format 32-bit floating point constants.

`.gfloat'
     This expects zero or more flonums, separated by commas, and
     assembles Vax `g' format 64-bit floating point constants.

`.hfloat'
     This expects zero or more flonums, separated by commas, and
     assembles Vax `h' format 128-bit floating point constants.



File: as.info,  Node: VAX-opcodes,  Next: VAX-branch,  Prev: VAX-directives,  Up: Vax-Dependent

8.32.4 VAX Opcodes
------------------

All DEC mnemonics are supported.  Beware that `case...' instructions
have exactly 3 operands.  The dispatch table that follows the `case...'
instruction should be made with `.word' statements.  This is compatible
with all unix assemblers we know of.


File: as.info,  Node: VAX-branch,  Next: VAX-operands,  Prev: VAX-opcodes,  Up: Vax-Dependent

8.32.5 VAX Branch Improvement
-----------------------------

Certain pseudo opcodes are permitted.  They are for branch
instructions.  They expand to the shortest branch instruction that
reaches the target.  Generally these mnemonics are made by substituting
`j' for `b' at the start of a DEC mnemonic.  This feature is included
both for compatibility and to help compilers.  If you do not need this
feature, avoid these opcodes.  Here are the mnemonics, and the code
they can expand into.

`jbsb'
     `Jsb' is already an instruction mnemonic, so we chose `jbsb'.
    (byte displacement)
          `bsbb ...'

    (word displacement)
          `bsbw ...'

    (long displacement)
          `jsb ...'

`jbr'
`jr'
     Unconditional branch.
    (byte displacement)
          `brb ...'

    (word displacement)
          `brw ...'

    (long displacement)
          `jmp ...'

`jCOND'
     COND may be any one of the conditional branches `neq', `nequ',
     `eql', `eqlu', `gtr', `geq', `lss', `gtru', `lequ', `vc', `vs',
     `gequ', `cc', `lssu', `cs'.  COND may also be one of the bit tests
     `bs', `bc', `bss', `bcs', `bsc', `bcc', `bssi', `bcci', `lbs',
     `lbc'.  NOTCOND is the opposite condition to COND.
    (byte displacement)
          `bCOND ...'

    (word displacement)
          `bNOTCOND foo ; brw ... ; foo:'

    (long displacement)
          `bNOTCOND foo ; jmp ... ; foo:'

`jacbX'
     X may be one of `b d f g h l w'.
    (word displacement)
          `OPCODE ...'

    (long displacement)
               OPCODE ..., foo ;
               brb bar ;
               foo: jmp ... ;
               bar:

`jaobYYY'
     YYY may be one of `lss leq'.

`jsobZZZ'
     ZZZ may be one of `geq gtr'.
    (byte displacement)
          `OPCODE ...'

    (word displacement)
               OPCODE ..., foo ;
               brb bar ;
               foo: brw DESTINATION ;
               bar:

    (long displacement)
               OPCODE ..., foo ;
               brb bar ;
               foo: jmp DESTINATION ;
               bar:

`aobleq'
`aoblss'
`sobgeq'
`sobgtr'

    (byte displacement)
          `OPCODE ...'

    (word displacement)
               OPCODE ..., foo ;
               brb bar ;
               foo: brw DESTINATION ;
               bar:

    (long displacement)
               OPCODE ..., foo ;
               brb bar ;
               foo: jmp DESTINATION ;
               bar:


File: as.info,  Node: VAX-operands,  Next: VAX-no,  Prev: VAX-branch,  Up: Vax-Dependent

8.32.6 VAX Operands
-------------------

The immediate character is `$' for Unix compatibility, not `#' as DEC
writes it.

   The indirect character is `*' for Unix compatibility, not `@' as DEC
writes it.

   The displacement sizing character is ``' (an accent grave) for Unix
compatibility, not `^' as DEC writes it.  The letter preceding ``' may
have either case.  `G' is not understood, but all other letters (`b i l
s w') are understood.

   Register names understood are `r0 r1 r2 ... r15 ap fp sp pc'.  Upper
and lower case letters are equivalent.

   For instance
     tstb *w`$4(r5)

   Any expression is permitted in an operand.  Operands are comma
separated.


File: as.info,  Node: VAX-no,  Prev: VAX-operands,  Up: Vax-Dependent

8.32.7 Not Supported on VAX
---------------------------

Vax bit fields can not be assembled with `as'.  Someone can add the
required code if they really need it.


File: as.info,  Node: V850-Dependent,  Next: Xtensa-Dependent,  Prev: TIC54X-Dependent,  Up: Machine Dependencies

8.33 v850 Dependent Features
============================

* Menu:

* V850 Options::              Options
* V850 Syntax::               Syntax
* V850 Floating Point::       Floating Point
* V850 Directives::           V850 Machine Directives
* V850 Opcodes::              Opcodes


File: as.info,  Node: V850 Options,  Next: V850 Syntax,  Up: V850-Dependent

8.33.1 Options
--------------

`as' supports the following additional command-line options for the
V850 processor family:

`-wsigned_overflow'
     Causes warnings to be produced when signed immediate values
     overflow the space available for then within their opcodes.  By
     default this option is disabled as it is possible to receive
     spurious warnings due to using exact bit patterns as immediate
     constants.

`-wunsigned_overflow'
     Causes warnings to be produced when unsigned immediate values
     overflow the space available for then within their opcodes.  By
     default this option is disabled as it is possible to receive
     spurious warnings due to using exact bit patterns as immediate
     constants.

`-mv850'
     Specifies that the assembled code should be marked as being
     targeted at the V850 processor.  This allows the linker to detect
     attempts to link such code with code assembled for other
     processors.

`-mv850e'
     Specifies that the assembled code should be marked as being
     targeted at the V850E processor.  This allows the linker to detect
     attempts to link such code with code assembled for other
     processors.

`-mv850e1'
     Specifies that the assembled code should be marked as being
     targeted at the V850E1 processor.  This allows the linker to
     detect attempts to link such code with code assembled for other
     processors.

`-mv850any'
     Specifies that the assembled code should be marked as being
     targeted at the V850 processor but support instructions that are
     specific to the extended variants of the process.  This allows the
     production of binaries that contain target specific code, but
     which are also intended to be used in a generic fashion.  For
     example libgcc.a contains generic routines used by the code
     produced by GCC for all versions of the v850 architecture,
     together with support routines only used by the V850E architecture.

`-mrelax'
     Enables relaxation.  This allows the .longcall and .longjump pseudo
     ops to be used in the assembler source code.  These ops label
     sections of code which are either a long function call or a long
     branch.  The assembler will then flag these sections of code and
     the linker will attempt to relax them.



File: as.info,  Node: V850 Syntax,  Next: V850 Floating Point,  Prev: V850 Options,  Up: V850-Dependent

8.33.2 Syntax
-------------

* Menu:

* V850-Chars::                Special Characters
* V850-Regs::                 Register Names


File: as.info,  Node: V850-Chars,  Next: V850-Regs,  Up: V850 Syntax

8.33.2.1 Special Characters
...........................

`#' is the line comment character.


File: as.info,  Node: V850-Regs,  Prev: V850-Chars,  Up: V850 Syntax

8.33.2.2 Register Names
.......................

`as' supports the following names for registers:
`general register 0'
     r0, zero

`general register 1'
     r1

`general register 2'
     r2, hp 

`general register 3'
     r3, sp 

`general register 4'
     r4, gp 

`general register 5'
     r5, tp

`general register 6'
     r6

`general register 7'
     r7

`general register 8'
     r8

`general register 9'
     r9

`general register 10'
     r10

`general register 11'
     r11

`general register 12'
     r12

`general register 13'
     r13

`general register 14'
     r14

`general register 15'
     r15

`general register 16'
     r16

`general register 17'
     r17

`general register 18'
     r18

`general register 19'
     r19

`general register 20'
     r20

`general register 21'
     r21

`general register 22'
     r22

`general register 23'
     r23

`general register 24'
     r24

`general register 25'
     r25

`general register 26'
     r26

`general register 27'
     r27

`general register 28'
     r28

`general register 29'
     r29 

`general register 30'
     r30, ep 

`general register 31'
     r31, lp 

`system register 0'
     eipc 

`system register 1'
     eipsw 

`system register 2'
     fepc 

`system register 3'
     fepsw 

`system register 4'
     ecr 

`system register 5'
     psw 

`system register 16'
     ctpc 

`system register 17'
     ctpsw 

`system register 18'
     dbpc 

`system register 19'
     dbpsw 

`system register 20'
     ctbp


File: as.info,  Node: V850 Floating Point,  Next: V850 Directives,  Prev: V850 Syntax,  Up: V850-Dependent

8.33.3 Floating Point
---------------------

The V850 family uses IEEE floating-point numbers.


File: as.info,  Node: V850 Directives,  Next: V850 Opcodes,  Prev: V850 Floating Point,  Up: V850-Dependent

8.33.4 V850 Machine Directives
------------------------------

`.offset <EXPRESSION>'
     Moves the offset into the current section to the specified amount.

`.section "name", <type>'
     This is an extension to the standard .section directive.  It sets
     the current section to be <type> and creates an alias for this
     section called "name".

`.v850'
     Specifies that the assembled code should be marked as being
     targeted at the V850 processor.  This allows the linker to detect
     attempts to link such code with code assembled for other
     processors.

`.v850e'
     Specifies that the assembled code should be marked as being
     targeted at the V850E processor.  This allows the linker to detect
     attempts to link such code with code assembled for other
     processors.

`.v850e1'
     Specifies that the assembled code should be marked as being
     targeted at the V850E1 processor.  This allows the linker to
     detect attempts to link such code with code assembled for other
     processors.



File: as.info,  Node: V850 Opcodes,  Prev: V850 Directives,  Up: V850-Dependent

8.33.5 Opcodes
--------------

`as' implements all the standard V850 opcodes.

   `as' also implements the following pseudo ops:

`hi0()'
     Computes the higher 16 bits of the given expression and stores it
     into the immediate operand field of the given instruction.  For
     example:

     `mulhi hi0(here - there), r5, r6'

     computes the difference between the address of labels 'here' and
     'there', takes the upper 16 bits of this difference, shifts it
     down 16 bits and then mutliplies it by the lower 16 bits in
     register 5, putting the result into register 6.

`lo()'
     Computes the lower 16 bits of the given expression and stores it
     into the immediate operand field of the given instruction.  For
     example:

     `addi lo(here - there), r5, r6'

     computes the difference between the address of labels 'here' and
     'there', takes the lower 16 bits of this difference and adds it to
     register 5, putting the result into register 6.

`hi()'
     Computes the higher 16 bits of the given expression and then adds
     the value of the most significant bit of the lower 16 bits of the
     expression and stores the result into the immediate operand field
     of the given instruction.  For example the following code can be
     used to compute the address of the label 'here' and store it into
     register 6:

     `movhi hi(here), r0, r6'     `movea lo(here), r6, r6'

     The reason for this special behaviour is that movea performs a sign
     extension on its immediate operand.  So for example if the address
     of 'here' was 0xFFFFFFFF then without the special behaviour of the
     hi() pseudo-op the movhi instruction would put 0xFFFF0000 into r6,
     then the movea instruction would takes its immediate operand,
     0xFFFF, sign extend it to 32 bits, 0xFFFFFFFF, and then add it
     into r6 giving 0xFFFEFFFF which is wrong (the fifth nibble is E).
     With the hi() pseudo op adding in the top bit of the lo() pseudo
     op, the movhi instruction actually stores 0 into r6 (0xFFFF + 1 =
     0x0000), so that the movea instruction stores 0xFFFFFFFF into r6 -
     the right value.

`hilo()'
     Computes the 32 bit value of the given expression and stores it
     into the immediate operand field of the given instruction (which
     must be a mov instruction).  For example:

     `mov hilo(here), r6'

     computes the absolute address of label 'here' and puts the result
     into register 6.

`sdaoff()'
     Computes the offset of the named variable from the start of the
     Small Data Area (whoes address is held in register 4, the GP
     register) and stores the result as a 16 bit signed value in the
     immediate operand field of the given instruction.  For example:

     `ld.w sdaoff(_a_variable)[gp],r6'

     loads the contents of the location pointed to by the label
     '_a_variable' into register 6, provided that the label is located
     somewhere within +/- 32K of the address held in the GP register.
     [Note the linker assumes that the GP register contains a fixed
     address set to the address of the label called '__gp'.  This can
     either be set up automatically by the linker, or specifically set
     by using the `--defsym __gp=<value>' command line option].

`tdaoff()'
     Computes the offset of the named variable from the start of the
     Tiny Data Area (whoes address is held in register 30, the EP
     register) and stores the result as a 4,5, 7 or 8 bit unsigned
     value in the immediate operand field of the given instruction.
     For example:

     `sld.w tdaoff(_a_variable)[ep],r6'

     loads the contents of the location pointed to by the label
     '_a_variable' into register 6, provided that the label is located
     somewhere within +256 bytes of the address held in the EP
     register.  [Note the linker assumes that the EP register contains
     a fixed address set to the address of the label called '__ep'.
     This can either be set up automatically by the linker, or
     specifically set by using the `--defsym __ep=<value>' command line
     option].

`zdaoff()'
     Computes the offset of the named variable from address 0 and
     stores the result as a 16 bit signed value in the immediate
     operand field of the given instruction.  For example:

     `movea zdaoff(_a_variable),zero,r6'

     puts the address of the label '_a_variable' into register 6,
     assuming that the label is somewhere within the first 32K of
     memory.  (Strictly speaking it also possible to access the last
     32K of memory as well, as the offsets are signed).

`ctoff()'
     Computes the offset of the named variable from the start of the
     Call Table Area (whoes address is helg in system register 20, the
     CTBP register) and stores the result a 6 or 16 bit unsigned value
     in the immediate field of then given instruction or piece of data.
     For example:

     `callt ctoff(table_func1)'

     will put the call the function whoes address is held in the call
     table at the location labeled 'table_func1'.

`.longcall `name''
     Indicates that the following sequence of instructions is a long
     call to function `name'.  The linker will attempt to shorten this
     call sequence if `name' is within a 22bit offset of the call.  Only
     valid if the `-mrelax' command line switch has been enabled.

`.longjump `name''
     Indicates that the following sequence of instructions is a long
     jump to label `name'.  The linker will attempt to shorten this code
     sequence if `name' is within a 22bit offset of the jump.  Only
     valid if the `-mrelax' command line switch has been enabled.


   For information on the V850 instruction set, see `V850 Family
32-/16-Bit single-Chip Microcontroller Architecture Manual' from NEC.
Ltd.


File: as.info,  Node: Xtensa-Dependent,  Next: Z80-Dependent,  Prev: V850-Dependent,  Up: Machine Dependencies

8.34 Xtensa Dependent Features
==============================

   This chapter covers features of the GNU assembler that are specific
to the Xtensa architecture.  For details about the Xtensa instruction
set, please consult the `Xtensa Instruction Set Architecture (ISA)
Reference Manual'.

* Menu:

* Xtensa Options::              Command-line Options.
* Xtensa Syntax::               Assembler Syntax for Xtensa Processors.
* Xtensa Optimizations::        Assembler Optimizations.
* Xtensa Relaxation::           Other Automatic Transformations.
* Xtensa Directives::           Directives for Xtensa Processors.


File: as.info,  Node: Xtensa Options,  Next: Xtensa Syntax,  Up: Xtensa-Dependent

8.34.1 Command Line Options
---------------------------

The Xtensa version of the GNU assembler supports these special options:

`--text-section-literals | --no-text-section-literals'
     Control the treatment of literal pools.  The default is
     `--no-text-section-literals', which places literals in a separate
     section in the output file.  This allows the literal pool to be
     placed in a data RAM/ROM.  With `--text-section-literals', the
     literals are interspersed in the text section in order to keep
     them as close as possible to their references.  This may be
     necessary for large assembly files, where the literals would
     otherwise be out of range of the `L32R' instructions in the text
     section.  These options only affect literals referenced via
     PC-relative `L32R' instructions; literals for absolute mode `L32R'
     instructions are handled separately.

`--absolute-literals | --no-absolute-literals'
     Indicate to the assembler whether `L32R' instructions use absolute
     or PC-relative addressing.  If the processor includes the absolute
     addressing option, the default is to use absolute `L32R'
     relocations.  Otherwise, only the PC-relative `L32R' relocations
     can be used.

`--target-align | --no-target-align'
     Enable or disable automatic alignment to reduce branch penalties
     at some expense in code size.  *Note Automatic Instruction
     Alignment: Xtensa Automatic Alignment.  This optimization is
     enabled by default.  Note that the assembler will always align
     instructions like `LOOP' that have fixed alignment requirements.

`--longcalls | --no-longcalls'
     Enable or disable transformation of call instructions to allow
     calls across a greater range of addresses.  *Note Function Call
     Relaxation: Xtensa Call Relaxation.  This option should be used
     when call targets can potentially be out of range.  It may degrade
     both code size and performance, but the linker can generally
     optimize away the unnecessary overhead when a call ends up within
     range.  The default is `--no-longcalls'.

`--transform | --no-transform'
     Enable or disable all assembler transformations of Xtensa
     instructions, including both relaxation and optimization.  The
     default is `--transform'; `--no-transform' should only be used in
     the rare cases when the instructions must be exactly as specified
     in the assembly source.  Using `--no-transform' causes out of range
     instruction operands to be errors.

`--rename-section OLDNAME=NEWNAME'
     Rename the OLDNAME section to NEWNAME.  This option can be used
     multiple times to rename multiple sections.


File: as.info,  Node: Xtensa Syntax,  Next: Xtensa Optimizations,  Prev: Xtensa Options,  Up: Xtensa-Dependent

8.34.2 Assembler Syntax
-----------------------

Block comments are delimited by `/*' and `*/'.  End of line comments
may be introduced with either `#' or `//'.

   Instructions consist of a leading opcode or macro name followed by
whitespace and an optional comma-separated list of operands:

     OPCODE [OPERAND, ...]

   Instructions must be separated by a newline or semicolon.

   FLIX instructions, which bundle multiple opcodes together in a single
instruction, are specified by enclosing the bundled opcodes inside
braces:

     {
     [FORMAT]
     OPCODE0 [OPERANDS]
     OPCODE1 [OPERANDS]
     OPCODE2 [OPERANDS]
     ...
     }

   The opcodes in a FLIX instruction are listed in the same order as the
corresponding instruction slots in the TIE format declaration.
Directives and labels are not allowed inside the braces of a FLIX
instruction.  A particular TIE format name can optionally be specified
immediately after the opening brace, but this is usually unnecessary.
The assembler will automatically search for a format that can encode the
specified opcodes, so the format name need only be specified in rare
cases where there is more than one applicable format and where it
matters which of those formats is used.  A FLIX instruction can also be
specified on a single line by separating the opcodes with semicolons:

     { [FORMAT;] OPCODE0 [OPERANDS]; OPCODE1 [OPERANDS]; OPCODE2 [OPERANDS]; ... }

   The assembler can automatically bundle opcodes into FLIX
instructions.  It encodes the opcodes in order, one at a time, choosing
the smallest format where each opcode can be encoded and filling unused
instruction slots with no-ops.

* Menu:

* Xtensa Opcodes::              Opcode Naming Conventions.
* Xtensa Registers::            Register Naming.


File: as.info,  Node: Xtensa Opcodes,  Next: Xtensa Registers,  Up: Xtensa Syntax

8.34.2.1 Opcode Names
.....................

See the `Xtensa Instruction Set Architecture (ISA) Reference Manual'
for a complete list of opcodes and descriptions of their semantics.

   If an opcode name is prefixed with an underscore character (`_'),
`as' will not transform that instruction in any way.  The underscore
prefix disables both optimization (*note Xtensa Optimizations: Xtensa
Optimizations.) and relaxation (*note Xtensa Relaxation: Xtensa
Relaxation.) for that particular instruction.  Only use the underscore
prefix when it is essential to select the exact opcode produced by the
assembler.  Using this feature unnecessarily makes the code less
efficient by disabling assembler optimization and less flexible by
disabling relaxation.

   Note that this special handling of underscore prefixes only applies
to Xtensa opcodes, not to either built-in macros or user-defined macros.
When an underscore prefix is used with a macro (e.g., `_MOV'), it
refers to a different macro.  The assembler generally provides built-in
macros both with and without the underscore prefix, where the underscore
versions behave as if the underscore carries through to the instructions
in the macros.  For example, `_MOV' may expand to `_MOV.N'.

   The underscore prefix only applies to individual instructions, not to
series of instructions.  For example, if a series of instructions have
underscore prefixes, the assembler will not transform the individual
instructions, but it may insert other instructions between them (e.g.,
to align a `LOOP' instruction).  To prevent the assembler from
modifying a series of instructions as a whole, use the `no-transform'
directive.  *Note transform: Transform Directive.


File: as.info,  Node: Xtensa Registers,  Prev: Xtensa Opcodes,  Up: Xtensa Syntax

8.34.2.2 Register Names
.......................

The assembly syntax for a register file entry is the "short" name for a
TIE register file followed by the index into that register file.  For
example, the general-purpose `AR' register file has a short name of
`a', so these registers are named `a0'...`a15'.  As a special feature,
`sp' is also supported as a synonym for `a1'.  Additional registers may
be added by processor configuration options and by designer-defined TIE
extensions.  An initial `$' character is optional in all register names.


File: as.info,  Node: Xtensa Optimizations,  Next: Xtensa Relaxation,  Prev: Xtensa Syntax,  Up: Xtensa-Dependent

8.34.3 Xtensa Optimizations
---------------------------

The optimizations currently supported by `as' are generation of density
instructions where appropriate and automatic branch target alignment.

* Menu:

* Density Instructions::        Using Density Instructions.
* Xtensa Automatic Alignment::  Automatic Instruction Alignment.


File: as.info,  Node: Density Instructions,  Next: Xtensa Automatic Alignment,  Up: Xtensa Optimizations

8.34.3.1 Using Density Instructions
...................................

The Xtensa instruction set has a code density option that provides
16-bit versions of some of the most commonly used opcodes.  Use of these
opcodes can significantly reduce code size.  When possible, the
assembler automatically translates instructions from the core Xtensa
instruction set into equivalent instructions from the Xtensa code
density option.  This translation can be disabled by using underscore
prefixes (*note Opcode Names: Xtensa Opcodes.), by using the
`--no-transform' command-line option (*note Command Line Options:
Xtensa Options.), or by using the `no-transform' directive (*note
transform: Transform Directive.).

   It is a good idea _not_ to use the density instructions directly.
The assembler will automatically select dense instructions where
possible.  If you later need to use an Xtensa processor without the code
density option, the same assembly code will then work without
modification.


File: as.info,  Node: Xtensa Automatic Alignment,  Prev: Density Instructions,  Up: Xtensa Optimizations

8.34.3.2 Automatic Instruction Alignment
........................................

The Xtensa assembler will automatically align certain instructions, both
to optimize performance and to satisfy architectural requirements.

   As an optimization to improve performance, the assembler attempts to
align branch targets so they do not cross instruction fetch boundaries.
(Xtensa processors can be configured with either 32-bit or 64-bit
instruction fetch widths.)  An instruction immediately following a call
is treated as a branch target in this context, because it will be the
target of a return from the call.  This alignment has the potential to
reduce branch penalties at some expense in code size.  The assembler
will not attempt to align labels with the prefixes `.Ln' and `.LM',
since these labels are used for debugging information and are not
typically branch targets.  This optimization is enabled by default.
You can disable it with the `--no-target-align' command-line option
(*note Command Line Options: Xtensa Options.).

   The target alignment optimization is done without adding instructions
that could increase the execution time of the program.  If there are
density instructions in the code preceding a target, the assembler can
change the target alignment by widening some of those instructions to
the equivalent 24-bit instructions.  Extra bytes of padding can be
inserted immediately following unconditional jump and return
instructions.  This approach is usually successful in aligning many,
but not all, branch targets.

   The `LOOP' family of instructions must be aligned such that the
first instruction in the loop body does not cross an instruction fetch
boundary (e.g., with a 32-bit fetch width, a `LOOP' instruction must be
on either a 1 or 2 mod 4 byte boundary).  The assembler knows about
this restriction and inserts the minimal number of 2 or 3 byte no-op
instructions to satisfy it.  When no-op instructions are added, any
label immediately preceding the original loop will be moved in order to
refer to the loop instruction, not the newly generated no-op
instruction.  To preserve binary compatibility across processors with
different fetch widths, the assembler conservatively assumes a 32-bit
fetch width when aligning `LOOP' instructions (except if the first
instruction in the loop is a 64-bit instruction).

   Similarly, the `ENTRY' instruction must be aligned on a 0 mod 4 byte
boundary.  The assembler satisfies this requirement by inserting zero
bytes when required.  In addition, labels immediately preceding the
`ENTRY' instruction will be moved to the newly aligned instruction
location.


File: as.info,  Node: Xtensa Relaxation,  Next: Xtensa Directives,  Prev: Xtensa Optimizations,  Up: Xtensa-Dependent

8.34.4 Xtensa Relaxation
------------------------

When an instruction operand is outside the range allowed for that
particular instruction field, `as' can transform the code to use a
functionally-equivalent instruction or sequence of instructions.  This
process is known as "relaxation".  This is typically done for branch
instructions because the distance of the branch targets is not known
until assembly-time.  The Xtensa assembler offers branch relaxation and
also extends this concept to function calls, `MOVI' instructions and
other instructions with immediate fields.

* Menu:

* Xtensa Branch Relaxation::        Relaxation of Branches.
* Xtensa Call Relaxation::          Relaxation of Function Calls.
* Xtensa Immediate Relaxation::     Relaxation of other Immediate Fields.


File: as.info,  Node: Xtensa Branch Relaxation,  Next: Xtensa Call Relaxation,  Up: Xtensa Relaxation

8.34.4.1 Conditional Branch Relaxation
......................................

When the target of a branch is too far away from the branch itself,
i.e., when the offset from the branch to the target is too large to fit
in the immediate field of the branch instruction, it may be necessary to
replace the branch with a branch around a jump.  For example,

         beqz    a2, L

   may result in:

         bnez.n  a2, M
         j L
     M:

   (The `BNEZ.N' instruction would be used in this example only if the
density option is available.  Otherwise, `BNEZ' would be used.)

   This relaxation works well because the unconditional jump instruction
has a much larger offset range than the various conditional branches.
However, an error will occur if a branch target is beyond the range of a
jump instruction.  `as' cannot relax unconditional jumps.  Similarly,
an error will occur if the original input contains an unconditional
jump to a target that is out of range.

   Branch relaxation is enabled by default.  It can be disabled by using
underscore prefixes (*note Opcode Names: Xtensa Opcodes.), the
`--no-transform' command-line option (*note Command Line Options:
Xtensa Options.), or the `no-transform' directive (*note transform:
Transform Directive.).


File: as.info,  Node: Xtensa Call Relaxation,  Next: Xtensa Immediate Relaxation,  Prev: Xtensa Branch Relaxation,  Up: Xtensa Relaxation

8.34.4.2 Function Call Relaxation
.................................

Function calls may require relaxation because the Xtensa immediate call
instructions (`CALL0', `CALL4', `CALL8' and `CALL12') provide a
PC-relative offset of only 512 Kbytes in either direction.  For larger
programs, it may be necessary to use indirect calls (`CALLX0',
`CALLX4', `CALLX8' and `CALLX12') where the target address is specified
in a register.  The Xtensa assembler can automatically relax immediate
call instructions into indirect call instructions.  This relaxation is
done by loading the address of the called function into the callee's
return address register and then using a `CALLX' instruction.  So, for
example:

         call8 func

   might be relaxed to:

         .literal .L1, func
         l32r    a8, .L1
         callx8  a8

   Because the addresses of targets of function calls are not generally
known until link-time, the assembler must assume the worst and relax all
the calls to functions in other source files, not just those that really
will be out of range.  The linker can recognize calls that were
unnecessarily relaxed, and it will remove the overhead introduced by the
assembler for those cases where direct calls are sufficient.

   Call relaxation is disabled by default because it can have a negative
effect on both code size and performance, although the linker can
usually eliminate the unnecessary overhead.  If a program is too large
and some of the calls are out of range, function call relaxation can be
enabled using the `--longcalls' command-line option or the `longcalls'
directive (*note longcalls: Longcalls Directive.).


File: as.info,  Node: Xtensa Immediate Relaxation,  Prev: Xtensa Call Relaxation,  Up: Xtensa Relaxation

8.34.4.3 Other Immediate Field Relaxation
.........................................

The assembler normally performs the following other relaxations.  They
can be disabled by using underscore prefixes (*note Opcode Names:
Xtensa Opcodes.), the `--no-transform' command-line option (*note
Command Line Options: Xtensa Options.), or the `no-transform' directive
(*note transform: Transform Directive.).

   The `MOVI' machine instruction can only materialize values in the
range from -2048 to 2047.  Values outside this range are best
materialized with `L32R' instructions.  Thus:

         movi a0, 100000

   is assembled into the following machine code:

         .literal .L1, 100000
         l32r a0, .L1

   The `L8UI' machine instruction can only be used with immediate
offsets in the range from 0 to 255. The `L16SI' and `L16UI' machine
instructions can only be used with offsets from 0 to 510.  The `L32I'
machine instruction can only be used with offsets from 0 to 1020.  A
load offset outside these ranges can be materalized with an `L32R'
instruction if the destination register of the load is different than
the source address register.  For example:

         l32i a1, a0, 2040

   is translated to:

         .literal .L1, 2040
         l32r a1, .L1
         addi a1, a0, a1
         l32i a1, a1, 0

If the load destination and source address register are the same, an
out-of-range offset causes an error.

   The Xtensa `ADDI' instruction only allows immediate operands in the
range from -128 to 127.  There are a number of alternate instruction
sequences for the `ADDI' operation.  First, if the immediate is 0, the
`ADDI' will be turned into a `MOV.N' instruction (or the equivalent
`OR' instruction if the code density option is not available).  If the
`ADDI' immediate is outside of the range -128 to 127, but inside the
range -32896 to 32639, an `ADDMI' instruction or `ADDMI'/`ADDI'
sequence will be used.  Finally, if the immediate is outside of this
range and a free register is available, an `L32R'/`ADD' sequence will
be used with a literal allocated from the literal pool.

   For example:

         addi    a5, a6, 0
         addi    a5, a6, 512
         addi    a5, a6, 513
         addi    a5, a6, 50000

   is assembled into the following:

         .literal .L1, 50000
         mov.n   a5, a6
         addmi   a5, a6, 0x200
         addmi   a5, a6, 0x200
         addi    a5, a5, 1
         l32r    a5, .L1
         add     a5, a6, a5


File: as.info,  Node: Xtensa Directives,  Prev: Xtensa Relaxation,  Up: Xtensa-Dependent

8.34.5 Directives
-----------------

The Xtensa assember supports a region-based directive syntax:

         .begin DIRECTIVE [OPTIONS]
         ...
         .end DIRECTIVE

   All the Xtensa-specific directives that apply to a region of code use
this syntax.

   The directive applies to code between the `.begin' and the `.end'.
The state of the option after the `.end' reverts to what it was before
the `.begin'.  A nested `.begin'/`.end' region can further change the
state of the directive without having to be aware of its outer state.
For example, consider:

         .begin no-transform
     L:  add a0, a1, a2
         .begin transform
     M:  add a0, a1, a2
         .end transform
     N:  add a0, a1, a2
         .end no-transform

   The `ADD' opcodes at `L' and `N' in the outer `no-transform' region
both result in `ADD' machine instructions, but the assembler selects an
`ADD.N' instruction for the `ADD' at `M' in the inner `transform'
region.

   The advantage of this style is that it works well inside macros
which can preserve the context of their callers.

   The following directives are available:

* Menu:

* Schedule Directive::         Enable instruction scheduling.
* Longcalls Directive::        Use Indirect Calls for Greater Range.
* Transform Directive::        Disable All Assembler Transformations.
* Literal Directive::          Intermix Literals with Instructions.
* Literal Position Directive:: Specify Inline Literal Pool Locations.
* Literal Prefix Directive::   Specify Literal Section Name Prefix.
* Absolute Literals Directive:: Control PC-Relative vs. Absolute Literals.


File: as.info,  Node: Schedule Directive,  Next: Longcalls Directive,  Up: Xtensa Directives

8.34.5.1 schedule
.................

The `schedule' directive is recognized only for compatibility with
Tensilica's assembler.

         .begin [no-]schedule
         .end [no-]schedule

   This directive is ignored and has no effect on `as'.


File: as.info,  Node: Longcalls Directive,  Next: Transform Directive,  Prev: Schedule Directive,  Up: Xtensa Directives

8.34.5.2 longcalls
..................

The `longcalls' directive enables or disables function call relaxation.
*Note Function Call Relaxation: Xtensa Call Relaxation.

         .begin [no-]longcalls
         .end [no-]longcalls

   Call relaxation is disabled by default unless the `--longcalls'
command-line option is specified.  The `longcalls' directive overrides
the default determined by the command-line options.


File: as.info,  Node: Transform Directive,  Next: Literal Directive,  Prev: Longcalls Directive,  Up: Xtensa Directives

8.34.5.3 transform
..................

This directive enables or disables all assembler transformation,
including relaxation (*note Xtensa Relaxation: Xtensa Relaxation.) and
optimization (*note Xtensa Optimizations: Xtensa Optimizations.).

         .begin [no-]transform
         .end [no-]transform

   Transformations are enabled by default unless the `--no-transform'
option is used.  The `transform' directive overrides the default
determined by the command-line options.  An underscore opcode prefix,
disabling transformation of that opcode, always takes precedence over
both directives and command-line flags.


File: as.info,  Node: Literal Directive,  Next: Literal Position Directive,  Prev: Transform Directive,  Up: Xtensa Directives

8.34.5.4 literal
................

The `.literal' directive is used to define literal pool data, i.e.,
read-only 32-bit data accessed via `L32R' instructions.

         .literal LABEL, VALUE[, VALUE...]

   This directive is similar to the standard `.word' directive, except
that the actual location of the literal data is determined by the
assembler and linker, not by the position of the `.literal' directive.
Using this directive gives the assembler freedom to locate the literal
data in the most appropriate place and possibly to combine identical
literals.  For example, the code:

         entry sp, 40
         .literal .L1, sym
         l32r    a4, .L1

   can be used to load a pointer to the symbol `sym' into register
`a4'.  The value of `sym' will not be placed between the `ENTRY' and
`L32R' instructions; instead, the assembler puts the data in a literal
pool.

   Literal pools for absolute mode `L32R' instructions (*note Absolute
Literals Directive::) are placed in a separate `.lit4' section.  By
default literal pools for PC-relative mode `L32R' instructions are
placed in a separate `.literal' section; however, when using the
`--text-section-literals' option (*note Command Line Options: Xtensa
Options.), the literal pools are placed in the current section.  These
text section literal pools are created automatically before `ENTRY'
instructions and manually after `.literal_position' directives (*note
literal_position: Literal Position Directive.).  If there are no
preceding `ENTRY' instructions, explicit `.literal_position' directives
must be used to place the text section literal pools; otherwise, `as'
will report an error.


File: as.info,  Node: Literal Position Directive,  Next: Literal Prefix Directive,  Prev: Literal Directive,  Up: Xtensa Directives

8.34.5.5 literal_position
.........................

When using `--text-section-literals' to place literals inline in the
section being assembled, the `.literal_position' directive can be used
to mark a potential location for a literal pool.

         .literal_position

   The `.literal_position' directive is ignored when the
`--text-section-literals' option is not used or when `L32R'
instructions use the absolute addressing mode.

   The assembler will automatically place text section literal pools
before `ENTRY' instructions, so the `.literal_position' directive is
only needed to specify some other location for a literal pool.  You may
need to add an explicit jump instruction to skip over an inline literal
pool.

   For example, an interrupt vector does not begin with an `ENTRY'
instruction so the assembler will be unable to automatically find a good
place to put a literal pool.  Moreover, the code for the interrupt
vector must be at a specific starting address, so the literal pool
cannot come before the start of the code.  The literal pool for the
vector must be explicitly positioned in the middle of the vector (before
any uses of the literals, due to the negative offsets used by
PC-relative `L32R' instructions).  The `.literal_position' directive
can be used to do this.  In the following code, the literal for `M'
will automatically be aligned correctly and is placed after the
unconditional jump.

         .global M
     code_start:
         j continue
         .literal_position
         .align 4
     continue:
         movi    a4, M


File: as.info,  Node: Literal Prefix Directive,  Next: Absolute Literals Directive,  Prev: Literal Position Directive,  Up: Xtensa Directives

8.34.5.6 literal_prefix
.......................

The `literal_prefix' directive allows you to specify different sections
to hold literals from different portions of an assembly file.  With
this directive, a single assembly file can be used to generate code
into multiple sections, including literals generated by the assembler.

         .begin literal_prefix [NAME]
         .end literal_prefix

   By default the assembler places literal pools in sections separate
from the instructions, using the default literal section names of
`.literal' for PC-relative mode `L32R' instructions and `.lit4' for
absolute mode `L32R' instructions (*note Absolute Literals
Directive::).  The `literal_prefix' directive causes different literal
sections to be used for the code inside the delimited region.  The new
literal sections are determined by including NAME as a prefix to the
default literal section names.  If the NAME argument is omitted, the
literal sections revert to the defaults.  This directive has no effect
when using the `--text-section-literals' option (*note Command Line
Options: Xtensa Options.).

   Except for two special cases, the assembler determines the new
literal sections by simply prepending NAME to the default section names,
resulting in `NAME.literal' and `NAME.lit4' sections.  The
`literal_prefix' directive is often used with the name of the current
text section as the prefix argument.  To facilitate this usage, the
assembler uses special case rules when it recognizes NAME as a text
section name.  First, if NAME ends with `.text', that suffix is not
included in the literal section name.  For example, if NAME is
`.iram0.text', then the literal sections will be `.iram0.literal' and
`.iram0.lit4'.  Second, if NAME begins with `.gnu.linkonce.t.', then
the literal section names are formed by replacing the `.t' substring
with `.literal' and `.lit4'.  For example, if NAME is
`.gnu.linkonce.t.func', the literal sections will be
`.gnu.linkonce.literal.func' and `.gnu.linkonce.lit4.func'.


File: as.info,  Node: Absolute Literals Directive,  Prev: Literal Prefix Directive,  Up: Xtensa Directives

8.34.5.7 absolute-literals
..........................

The `absolute-literals' and `no-absolute-literals' directives control
the absolute vs. PC-relative mode for `L32R' instructions.  These are
relevant only for Xtensa configurations that include the absolute
addressing option for `L32R' instructions.

         .begin [no-]absolute-literals
         .end [no-]absolute-literals

   These directives do not change the `L32R' mode--they only cause the
assembler to emit the appropriate kind of relocation for `L32R'
instructions and to place the literal values in the appropriate section.
To change the `L32R' mode, the program must write the `LITBASE' special
register.  It is the programmer's responsibility to keep track of the
mode and indicate to the assembler which mode is used in each region of
code.

   If the Xtensa configuration includes the absolute `L32R' addressing
option, the default is to assume absolute `L32R' addressing unless the
`--no-absolute-literals' command-line option is specified.  Otherwise,
the default is to assume PC-relative `L32R' addressing.  The
`absolute-literals' directive can then be used to override the default
determined by the command-line options.


File: as.info,  Node: Reporting Bugs,  Next: Acknowledgements,  Prev: Machine Dependencies,  Up: Top

9 Reporting Bugs
****************

Your bug reports play an essential role in making `as' reliable.

   Reporting a bug may help you by bringing a solution to your problem,
or it may not.  But in any case the principal function of a bug report
is to help the entire community by making the next version of `as' work
better.  Bug reports are your contribution to the maintenance of `as'.

   In order for a bug report to serve its purpose, you must include the
information that enables us to fix the bug.

* Menu:

* Bug Criteria::                Have you found a bug?
* Bug Reporting::               How to report bugs


File: as.info,  Node: Bug Criteria,  Next: Bug Reporting,  Up: Reporting Bugs

9.1 Have You Found a Bug?
=========================

If you are not sure whether you have found a bug, here are some
guidelines:

   * If the assembler gets a fatal signal, for any input whatever, that
     is a `as' bug.  Reliable assemblers never crash.

   * If `as' produces an error message for valid input, that is a bug.

   * If `as' does not produce an error message for invalid input, that
     is a bug.  However, you should note that your idea of "invalid
     input" might be our idea of "an extension" or "support for
     traditional practice".

   * If you are an experienced user of assemblers, your suggestions for
     improvement of `as' are welcome in any case.


File: as.info,  Node: Bug Reporting,  Prev: Bug Criteria,  Up: Reporting Bugs

9.2 How to Report Bugs
======================

A number of companies and individuals offer support for GNU products.
If you obtained `as' from a support organization, we recommend you
contact that organization first.

   You can find contact information for many support companies and
individuals in the file `etc/SERVICE' in the GNU Emacs distribution.

   In any event, we also recommend that you send bug reports for `as'
to `bug-binutils@gnu.org'.

   The fundamental principle of reporting bugs usefully is this:
*report all the facts*.  If you are not sure whether to state a fact or
leave it out, state it!

   Often people omit facts because they think they know what causes the
problem and assume that some details do not matter.  Thus, you might
assume that the name of a symbol you use in an example does not matter.
Well, probably it does not, but one cannot be sure.  Perhaps the bug
is a stray memory reference which happens to fetch from the location
where that name is stored in memory; perhaps, if the name were
different, the contents of that location would fool the assembler into
doing the right thing despite the bug.  Play it safe and give a
specific, complete example.  That is the easiest thing for you to do,
and the most helpful.

   Keep in mind that the purpose of a bug report is to enable us to fix
the bug if it is new to us.  Therefore, always write your bug reports
on the assumption that the bug has not been reported previously.

   Sometimes people give a few sketchy facts and ask, "Does this ring a
bell?"  This cannot help us fix a bug, so it is basically useless.  We
respond by asking for enough details to enable us to investigate.  You
might as well expedite matters by sending them to begin with.

   To enable us to fix the bug, you should include all these things:

   * The version of `as'.  `as' announces it if you start it with the
     `--version' argument.

     Without this, we will not know whether there is any point in
     looking for the bug in the current version of `as'.

   * Any patches you may have applied to the `as' source.

   * The type of machine you are using, and the operating system name
     and version number.

   * What compiler (and its version) was used to compile `as'--e.g.
     "`gcc-2.7'".

   * The command arguments you gave the assembler to assemble your
     example and observe the bug.  To guarantee you will not omit
     something important, list them all.  A copy of the Makefile (or
     the output from make) is sufficient.

     If we were to try to guess the arguments, we would probably guess
     wrong and then we might not encounter the bug.

   * A complete input file that will reproduce the bug.  If the bug is
     observed when the assembler is invoked via a compiler, send the
     assembler source, not the high level language source.  Most
     compilers will produce the assembler source when run with the `-S'
     option.  If you are using `gcc', use the options `-v
     --save-temps'; this will save the assembler source in a file with
     an extension of `.s', and also show you exactly how `as' is being
     run.

   * A description of what behavior you observe that you believe is
     incorrect.  For example, "It gets a fatal signal."

     Of course, if the bug is that `as' gets a fatal signal, then we
     will certainly notice it.  But if the bug is incorrect output, we
     might not notice unless it is glaringly wrong.  You might as well
     not give us a chance to make a mistake.

     Even if the problem you experience is a fatal signal, you should
     still say so explicitly.  Suppose something strange is going on,
     such as, your copy of `as' is out of synch, or you have
     encountered a bug in the C library on your system.  (This has
     happened!)  Your copy might crash and ours would not.  If you told
     us to expect a crash, then when ours fails to crash, we would know
     that the bug was not happening for us.  If you had not told us to
     expect a crash, then we would not be able to draw any conclusion
     from our observations.

   * If you wish to suggest changes to the `as' source, send us context
     diffs, as generated by `diff' with the `-u', `-c', or `-p' option.
     Always send diffs from the old file to the new file.  If you even
     discuss something in the `as' source, refer to it by context, not
     by line number.

     The line numbers in our development sources will not match those
     in your sources.  Your line numbers would convey no useful
     information to us.

   Here are some things that are not necessary:

   * A description of the envelope of the bug.

     Often people who encounter a bug spend a lot of time investigating
     which changes to the input file will make the bug go away and which
     changes will not affect it.

     This is often time consuming and not very useful, because the way
     we will find the bug is by running a single example under the
     debugger with breakpoints, not by pure deduction from a series of
     examples.  We recommend that you save your time for something else.

     Of course, if you can find a simpler example to report _instead_
     of the original one, that is a convenience for us.  Errors in the
     output will be easier to spot, running under the debugger will take
     less time, and so on.

     However, simplification is not vital; if you do not want to do
     this, report the bug anyway and send us the entire test case you
     used.

   * A patch for the bug.

     A patch for the bug does help us if it is a good one.  But do not
     omit the necessary information, such as the test case, on the
     assumption that a patch is all we need.  We might see problems
     with your patch and decide to fix the problem another way, or we
     might not understand it at all.

     Sometimes with a program as complicated as `as' it is very hard to
     construct an example that will make the program follow a certain
     path through the code.  If you do not send us the example, we will
     not be able to construct one, so we will not be able to verify
     that the bug is fixed.

     And if we cannot understand what bug you are trying to fix, or why
     your patch should be an improvement, we will not install it.  A
     test case will help us to understand.

   * A guess about what the bug is or what it depends on.

     Such guesses are usually wrong.  Even we cannot guess right about
     such things without first using the debugger to find the facts.


File: as.info,  Node: Acknowledgements,  Next: GNU Free Documentation License,  Prev: Reporting Bugs,  Up: Top

10 Acknowledgements
*******************

If you have contributed to GAS and your name isn't listed here, it is
not meant as a slight.  We just don't know about it.  Send mail to the
maintainer, and we'll correct the situation.  Currently the maintainer
is Ken Raeburn (email address `raeburn@cygnus.com').

   Dean Elsner wrote the original GNU assembler for the VAX.(1)

   Jay Fenlason maintained GAS for a while, adding support for
GDB-specific debug information and the 68k series machines, most of the
preprocessing pass, and extensive changes in `messages.c',
`input-file.c', `write.c'.

   K. Richard Pixley maintained GAS for a while, adding various
enhancements and many bug fixes, including merging support for several
processors, breaking GAS up to handle multiple object file format back
ends (including heavy rewrite, testing, an integration of the coff and
b.out back ends), adding configuration including heavy testing and
verification of cross assemblers and file splits and renaming,
converted GAS to strictly ANSI C including full prototypes, added
support for m680[34]0 and cpu32, did considerable work on i960
including a COFF port (including considerable amounts of reverse
engineering), a SPARC opcode file rewrite, DECstation, rs6000, and
hp300hpux host ports, updated "know" assertions and made them work,
much other reorganization, cleanup, and lint.

   Ken Raeburn wrote the high-level BFD interface code to replace most
of the code in format-specific I/O modules.

   The original VMS support was contributed by David L. Kashtan.  Eric
Youngdale has done much work with it since.

   The Intel 80386 machine description was written by Eliot Dresselhaus.

   Minh Tran-Le at IntelliCorp contributed some AIX 386 support.

   The Motorola 88k machine description was contributed by Devon Bowen
of Buffalo University and Torbjorn Granlund of the Swedish Institute of
Computer Science.

   Keith Knowles at the Open Software Foundation wrote the original
MIPS back end (`tc-mips.c', `tc-mips.h'), and contributed Rose format
support (which hasn't been merged in yet).  Ralph Campbell worked with
the MIPS code to support a.out format.

   Support for the Zilog Z8k and Renesas H8/300 processors (tc-z8k,
tc-h8300), and IEEE 695 object file format (obj-ieee), was written by
Steve Chamberlain of Cygnus Support.  Steve also modified the COFF back
end to use BFD for some low-level operations, for use with the H8/300
and AMD 29k targets.

   John Gilmore built the AMD 29000 support, added `.include' support,
and simplified the configuration of which versions accept which
directives.  He updated the 68k machine description so that Motorola's
opcodes always produced fixed-size instructions (e.g., `jsr'), while
synthetic instructions remained shrinkable (`jbsr').  John fixed many
bugs, including true tested cross-compilation support, and one bug in
relaxation that took a week and required the proverbial one-bit fix.

   Ian Lance Taylor of Cygnus Support merged the Motorola and MIT
syntax for the 68k, completed support for some COFF targets (68k, i386
SVR3, and SCO Unix), added support for MIPS ECOFF and ELF targets,
wrote the initial RS/6000 and PowerPC assembler, and made a few other
minor patches.

   Steve Chamberlain made GAS able to generate listings.

   Hewlett-Packard contributed support for the HP9000/300.

   Jeff Law wrote GAS and BFD support for the native HPPA object format
(SOM) along with a fairly extensive HPPA testsuite (for both SOM and
ELF object formats).  This work was supported by both the Center for
Software Science at the University of Utah and Cygnus Support.

   Support for ELF format files has been worked on by Mark Eichin of
Cygnus Support (original, incomplete implementation for SPARC), Pete
Hoogenboom and Jeff Law at the University of Utah (HPPA mainly),
Michael Meissner of the Open Software Foundation (i386 mainly), and Ken
Raeburn of Cygnus Support (sparc, and some initial 64-bit support).

   Linas Vepstas added GAS support for the ESA/390 "IBM 370"
architecture.

   Richard Henderson rewrote the Alpha assembler. Klaus Kaempf wrote
GAS and BFD support for openVMS/Alpha.

   Timothy Wall, Michael Hayes, and Greg Smart contributed to the
various tic* flavors.

   David Heine, Sterling Augustine, Bob Wilson and John Ruttenberg from
Tensilica, Inc. added support for Xtensa processors.

   Several engineers at Cygnus Support have also provided many small
bug fixes and configuration enhancements.

   Many others have contributed large or small bugfixes and
enhancements.  If you have contributed significant work and are not
mentioned on this list, and want to be, let us know.  Some of the
history has been lost; we are not intentionally leaving anyone out.

   ---------- Footnotes ----------

   (1) Any more details?


File: as.info,  Node: GNU Free Documentation License,  Next: Index,  Prev: Acknowledgements,  Up: Top

Appendix A GNU Free Documentation License
*****************************************

                        Version 1.1, March 2000

     Copyright (C) 2000, 2003 Free Software Foundation, Inc.
     51 Franklin Street, Fifth Floor, Boston, MA  02110-1301  USA

     Everyone is permitted to copy and distribute verbatim copies
     of this license document, but changing it is not allowed.


  0. PREAMBLE

     The purpose of this License is to make a manual, textbook, or other
     written document "free" in the sense of freedom: to assure everyone
     the effective freedom to copy and redistribute it, with or without
     modifying it, either commercially or noncommercially.  Secondarily,
     this License preserves for the author and publisher a way to get
     credit for their work, while not being considered responsible for
     modifications made by others.

     This License is a kind of "copyleft", which means that derivative
     works of the document must themselves be free in the same sense.
     It complements the GNU General Public License, which is a copyleft
     license designed for free software.

     We have designed this License in order to use it for manuals for
     free software, because free software needs free documentation: a
     free program should come with manuals providing the same freedoms
     that the software does.  But this License is not limited to
     software manuals; it can be used for any textual work, regardless
     of subject matter or whether it is published as a printed book.
     We recommend this License principally for works whose purpose is
     instruction or reference.


  1. APPLICABILITY AND DEFINITIONS

     This License applies to any manual or other work that contains a
     notice placed by the copyright holder saying it can be distributed
     under the terms of this License.  The "Document", below, refers to
     any such manual or work.  Any member of the public is a licensee,
     and is addressed as "you."

     A "Modified Version" of the Document means any work containing the
     Document or a portion of it, either copied verbatim, or with
     modifications and/or translated into another language.

     A "Secondary Section" is a named appendix or a front-matter
     section of the Document that deals exclusively with the
     relationship of the publishers or authors of the Document to the
     Document's overall subject (or to related matters) and contains
     nothing that could fall directly within that overall subject.
     (For example, if the Document is in part a textbook of
     mathematics, a Secondary Section may not explain any mathematics.)
     The relationship could be a matter of historical connection with
     the subject or with related matters, or of legal, commercial,
     philosophical, ethical or political position regarding them.

     The "Invariant Sections" are certain Secondary Sections whose
     titles are designated, as being those of Invariant Sections, in
     the notice that says that the Document is released under this
     License.

     The "Cover Texts" are certain short passages of text that are
     listed, as Front-Cover Texts or Back-Cover Texts, in the notice
     that says that the Document is released under this License.

     A "Transparent" copy of the Document means a machine-readable copy,
     represented in a format whose specification is available to the
     general public, whose contents can be viewed and edited directly
     and straightforwardly with generic text editors or (for images
     composed of pixels) generic paint programs or (for drawings) some
     widely available drawing editor, and that is suitable for input to
     text formatters or for automatic translation to a variety of
     formats suitable for input to text formatters.  A copy made in an
     otherwise Transparent file format whose markup has been designed
     to thwart or discourage subsequent modification by readers is not
     Transparent.  A copy that is not "Transparent" is called "Opaque."

     Examples of suitable formats for Transparent copies include plain
     ASCII without markup, Texinfo input format, LaTeX input format,
     SGML or XML using a publicly available DTD, and
     standard-conforming simple HTML designed for human modification.
     Opaque formats include PostScript, PDF, proprietary formats that
     can be read and edited only by proprietary word processors, SGML
     or XML for which the DTD and/or processing tools are not generally
     available, and the machine-generated HTML produced by some word
     processors for output purposes only.

     The "Title Page" means, for a printed book, the title page itself,
     plus such following pages as are needed to hold, legibly, the
     material this License requires to appear in the title page.  For
     works in formats which do not have any title page as such, "Title
     Page" means the text near the most prominent appearance of the
     work's title, preceding the beginning of the body of the text.

  2. VERBATIM COPYING

     You may copy and distribute the Document in any medium, either
     commercially or noncommercially, provided that this License, the
     copyright notices, and the license notice saying this License
     applies to the Document are reproduced in all copies, and that you
     add no other conditions whatsoever to those of this License.  You
     may not use technical measures to obstruct or control the reading
     or further copying of the copies you make or distribute.  However,
     you may accept compensation in exchange for copies.  If you
     distribute a large enough number of copies you must also follow
     the conditions in section 3.

     You may also lend copies, under the same conditions stated above,
     and you may publicly display copies.

  3. COPYING IN QUANTITY

     If you publish printed copies of the Document numbering more than
     100, and the Document's license notice requires Cover Texts, you
     must enclose the copies in covers that carry, clearly and legibly,
     all these Cover Texts: Front-Cover Texts on the front cover, and
     Back-Cover Texts on the back cover.  Both covers must also clearly
     and legibly identify you as the publisher of these copies.  The
     front cover must present the full title with all words of the
     title equally prominent and visible.  You may add other material
     on the covers in addition.  Copying with changes limited to the
     covers, as long as they preserve the title of the Document and
     satisfy these conditions, can be treated as verbatim copying in
     other respects.

     If the required texts for either cover are too voluminous to fit
     legibly, you should put the first ones listed (as many as fit
     reasonably) on the actual cover, and continue the rest onto
     adjacent pages.

     If you publish or distribute Opaque copies of the Document
     numbering more than 100, you must either include a
     machine-readable Transparent copy along with each Opaque copy, or
     state in or with each Opaque copy a publicly-accessible
     computer-network location containing a complete Transparent copy
     of the Document, free of added material, which the general
     network-using public has access to download anonymously at no
     charge using public-standard network protocols.  If you use the
     latter option, you must take reasonably prudent steps, when you
     begin distribution of Opaque copies in quantity, to ensure that
     this Transparent copy will remain thus accessible at the stated
     location until at least one year after the last time you
     distribute an Opaque copy (directly or through your agents or
     retailers) of that edition to the public.

     It is requested, but not required, that you contact the authors of
     the Document well before redistributing any large number of
     copies, to give them a chance to provide you with an updated
     version of the Document.

  4. MODIFICATIONS

     You may copy and distribute a Modified Version of the Document
     under the conditions of sections 2 and 3 above, provided that you
     release the Modified Version under precisely this License, with
     the Modified Version filling the role of the Document, thus
     licensing distribution and modification of the Modified Version to
     whoever possesses a copy of it.  In addition, you must do these
     things in the Modified Version:

     A. Use in the Title Page (and on the covers, if any) a title
     distinct    from that of the Document, and from those of previous
     versions    (which should, if there were any, be listed in the
     History section    of the Document).  You may use the same title
     as a previous version    if the original publisher of that version
     gives permission.
     B. List on the Title Page, as authors, one or more persons or
     entities    responsible for authorship of the modifications in the
     Modified    Version, together with at least five of the principal
     authors of the    Document (all of its principal authors, if it
     has less than five).
     C. State on the Title page the name of the publisher of the
     Modified Version, as the publisher.
     D. Preserve all the copyright notices of the Document.
     E. Add an appropriate copyright notice for your modifications
     adjacent to the other copyright notices.
     F. Include, immediately after the copyright notices, a license
     notice    giving the public permission to use the Modified Version
     under the    terms of this License, in the form shown in the
     Addendum below.
     G. Preserve in that license notice the full lists of Invariant
     Sections    and required Cover Texts given in the Document's
     license notice.
     H. Include an unaltered copy of this License.
     I. Preserve the section entitled "History", and its title, and add
     to    it an item stating at least the title, year, new authors, and
       publisher of the Modified Version as given on the Title Page.
     If    there is no section entitled "History" in the Document,
     create one    stating the title, year, authors, and publisher of
     the Document as    given on its Title Page, then add an item
     describing the Modified    Version as stated in the previous
     sentence.
     J. Preserve the network location, if any, given in the Document for
       public access to a Transparent copy of the Document, and
     likewise    the network locations given in the Document for
     previous versions    it was based on.  These may be placed in the
     "History" section.     You may omit a network location for a work
     that was published at    least four years before the Document
     itself, or if the original    publisher of the version it refers
     to gives permission.
     K. In any section entitled "Acknowledgements" or "Dedications",
     preserve the section's title, and preserve in the section all the
      substance and tone of each of the contributor acknowledgements
     and/or dedications given therein.
     L. Preserve all the Invariant Sections of the Document,
     unaltered in their text and in their titles.  Section numbers
     or the equivalent are not considered part of the section titles.
     M. Delete any section entitled "Endorsements."  Such a section
     may not be included in the Modified Version.
     N. Do not retitle any existing section as "Endorsements"    or to
     conflict in title with any Invariant Section.

     If the Modified Version includes new front-matter sections or
     appendices that qualify as Secondary Sections and contain no
     material copied from the Document, you may at your option
     designate some or all of these sections as invariant.  To do this,
     add their titles to the list of Invariant Sections in the Modified
     Version's license notice.  These titles must be distinct from any
     other section titles.

     You may add a section entitled "Endorsements", provided it contains
     nothing but endorsements of your Modified Version by various
     parties-for example, statements of peer review or that the text has
     been approved by an organization as the authoritative definition
     of a standard.

     You may add a passage of up to five words as a Front-Cover Text,
     and a passage of up to 25 words as a Back-Cover Text, to the end
     of the list of Cover Texts in the Modified Version.  Only one
     passage of Front-Cover Text and one of Back-Cover Text may be
     added by (or through arrangements made by) any one entity.  If the
     Document already includes a cover text for the same cover,
     previously added by you or by arrangement made by the same entity
     you are acting on behalf of, you may not add another; but you may
     replace the old one, on explicit permission from the previous
     publisher that added the old one.

     The author(s) and publisher(s) of the Document do not by this
     License give permission to use their names for publicity for or to
     assert or imply endorsement of any Modified Version.

  5. COMBINING DOCUMENTS

     You may combine the Document with other documents released under
     this License, under the terms defined in section 4 above for
     modified versions, provided that you include in the combination
     all of the Invariant Sections of all of the original documents,
     unmodified, and list them all as Invariant Sections of your
     combined work in its license notice.

     The combined work need only contain one copy of this License, and
     multiple identical Invariant Sections may be replaced with a single
     copy.  If there are multiple Invariant Sections with the same name
     but different contents, make the title of each such section unique
     by adding at the end of it, in parentheses, the name of the
     original author or publisher of that section if known, or else a
     unique number.  Make the same adjustment to the section titles in
     the list of Invariant Sections in the license notice of the
     combined work.

     In the combination, you must combine any sections entitled
     "History" in the various original documents, forming one section
     entitled "History"; likewise combine any sections entitled
     "Acknowledgements", and any sections entitled "Dedications."  You
     must delete all sections entitled "Endorsements."

  6. COLLECTIONS OF DOCUMENTS

     You may make a collection consisting of the Document and other
     documents released under this License, and replace the individual
     copies of this License in the various documents with a single copy
     that is included in the collection, provided that you follow the
     rules of this License for verbatim copying of each of the
     documents in all other respects.

     You may extract a single document from such a collection, and
     distribute it individually under this License, provided you insert
     a copy of this License into the extracted document, and follow
     this License in all other respects regarding verbatim copying of
     that document.

  7. AGGREGATION WITH INDEPENDENT WORKS

     A compilation of the Document or its derivatives with other
     separate and independent documents or works, in or on a volume of
     a storage or distribution medium, does not as a whole count as a
     Modified Version of the Document, provided no compilation
     copyright is claimed for the compilation.  Such a compilation is
     called an "aggregate", and this License does not apply to the
     other self-contained works thus compiled with the Document, on
     account of their being thus compiled, if they are not themselves
     derivative works of the Document.

     If the Cover Text requirement of section 3 is applicable to these
     copies of the Document, then if the Document is less than one
     quarter of the entire aggregate, the Document's Cover Texts may be
     placed on covers that surround only the Document within the
     aggregate.  Otherwise they must appear on covers around the whole
     aggregate.

  8. TRANSLATION

     Translation is considered a kind of modification, so you may
     distribute translations of the Document under the terms of section
     4.  Replacing Invariant Sections with translations requires special
     permission from their copyright holders, but you may include
     translations of some or all Invariant Sections in addition to the
     original versions of these Invariant Sections.  You may include a
     translation of this License provided that you also include the
     original English version of this License.  In case of a
     disagreement between the translation and the original English
     version of this License, the original English version will prevail.

  9. TERMINATION

     You may not copy, modify, sublicense, or distribute the Document
     except as expressly provided for under this License.  Any other
     attempt to copy, modify, sublicense or distribute the Document is
     void, and will automatically terminate your rights under this
     License.  However, parties who have received copies, or rights,
     from you under this License will not have their licenses
     terminated so long as such parties remain in full compliance.

 10. FUTURE REVISIONS OF THIS LICENSE

     The Free Software Foundation may publish new, revised versions of
     the GNU Free Documentation License from time to time.  Such new
     versions will be similar in spirit to the present version, but may
     differ in detail to address new problems or concerns.  See
     http://www.gnu.org/copyleft/.

     Each version of the License is given a distinguishing version
     number.  If the Document specifies that a particular numbered
     version of this License "or any later version" applies to it, you
     have the option of following the terms and conditions either of
     that specified version or of any later version that has been
     published (not as a draft) by the Free Software Foundation.  If
     the Document does not specify a version number of this License,
     you may choose any version ever published (not as a draft) by the
     Free Software Foundation.


ADDENDUM: How to use this License for your documents
====================================================

To use this License in a document you have written, include a copy of
the License in the document and put the following copyright and license
notices just after the title page:

     Copyright (C)  YEAR  YOUR NAME.
     Permission is granted to copy, distribute and/or modify this document
     under the terms of the GNU Free Documentation License, Version 1.1
     or any later version published by the Free Software Foundation;
     with the Invariant Sections being LIST THEIR TITLES, with the
     Front-Cover Texts being LIST, and with the Back-Cover Texts being LIST.
     A copy of the license is included in the section entitled "GNU
     Free Documentation License."

   If you have no Invariant Sections, write "with no Invariant Sections"
instead of saying which ones are invariant.  If you have no Front-Cover
Texts, write "no Front-Cover Texts" instead of "Front-Cover Texts being
LIST"; likewise for Back-Cover Texts.

   If your document contains nontrivial examples of program code, we
recommend releasing these examples in parallel under your choice of
free software license, such as the GNU General Public License, to
permit their use in free software.


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